Power transmission device for vehicle

ABSTRACT

An output shaft is arranged to be lateral and parallel to engine input shafts and a motor input shaft. An engine side gear mechanism for transmitting a power of the engine input shafts to the output shaft is provided. A motor side gear mechanism for transmitting a power of the motor input shaft to the output shaft is provided. An input side clutch engages and disengages the engine input shafts and the motor input shaft. When the input side clutch is engaged, the power transmission between a position where the engine side gear mechanism is arranged on the engine input shafts and a position where the motor side gear mechanism is arranged on the motor input shaft is invariably possible.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional of U.S. application Ser. No. 13/178,625 filed Jul.8, 2011 which claims priority to and is based on Japanese PatentApplication No. 2010-155874 filed on Jul. 8, 2010 and No. 2011-20690filed on Feb. 2, 2011, the contents of each of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power transmission device for avehicle and is suitably used for a hybrid vehicle.

2. Description of Related Art

Conventionally, as a power transmission device used for a hybridvehicle, there has been known a device described in Patent document 1(JP-A-H09-123773). As shown in FIG. 1 of Patent document 1, the powertransmission device has an engine input shaft 32, to which a powergenerated by an engine 51 is inputted, and a cylindrical first outputshaft 33, to which second and fourth gears are attached. The powertransmission device is structured such that the engine input shaft 32and the cylindrical first output shaft 33 are engaged and disengaged bya first clutch 36. Also, the power transmission device has a cylindricalsecond output shaft 34, to which first and third gears are attached. Thepower transmission device is structured such that the engine input shaft32 and the cylindrical second output shaft 34 are engaged and disengagedby a second clutch 37. A power generated by a motor 53 is also inputtedto the second output shaft 34.

By employing such the construction, the engine 51 can use not only thesecond and fourth gears of the first output shaft 33 but also the firstand third gears on the motor 53 side by engaging the second clutch 37.The motor 53 can use not only the first and third gears on the motor 53side but also the second and fourth gears by engaging the first clutch36 and the second clutch 37.

As described above, as a construction for increasing variations of gearselection, the power transmission device is structured such that thepower can be transmitted from the engine input shaft 32 to the secondand fourth gears and the first and third gears through the first clutch36 and the second clutch 37 respectively. That is, the first to fourthgears can be commonly used by the engine 51 and the motor 53.

However, in the power transmission device of Patent document 1, it isnecessary to provide the clutch 36 dedicated to a power transmissionroute from the engine input shaft 32 to the first output shaft 33(second and fourth gears) and the clutch 37 dedicated to a powertransmission route from the engine input shaft 32 to the second outputshaft 34 (first and third gears) individually. Therefore, the number ofthe clutches is increased, and eventually an entire size of the powertransmission device enlarges.

SUMMARY OF THE INVENTION

It is an object of the present invention to reduce as much as possiblethe number of clutches in a vehicular power transmission device thattransmits a power of an engine and a power of a motor to an axle whileenabling a gear mechanism to be commonly used by the engine and themotor.

According to a first example aspect of the present invention, avehicular power transmission device transmits powers generated by anengine and a motor to an axle of a vehicle. The power transmissiondevice has an engine input shaft, to which the power generated by theengine is inputted and which transmits the inputted power of the engine,a motor input shaft, to which the power generated by the motor isinputted and which transmits the inputted power of the motor, an outputshaft for outputting the power to be transmitted to the axle, an engineside gear mechanism provided to the engine input shaft for transmittingthe power of the engine input shaft to the output shaft not through themotor input shaft, a first motor side gear mechanism provided to themotor input shaft for transmitting the power of the motor input shaft tothe output shaft not through the engine input shaft, and an input sideclutch for engaging and disengaging the engine input shaft and the motorinput shaft. When the input side clutch is engaged, the powertransmission is enabled between the engine side gear mechanism on theengine input shaft and the first motor side gear mechanism on the motorinput shaft.

With such the construction, by engaging the input side clutch, theengine and the motor can commonly use the engine side gear mechanism orthe first motor side gear mechanism. If the input side clutch isdisengaged, the motor can use the first motor side gear mechanism whilethe engine uses the engine side gear mechanism.

When the input side clutch is engaged, the power can be invariablytransmitted between the position where the engine side gear mechanism isarranged and the position where the first motor side gear mechanism isarranged. This means that no clutch other than the input side clutch isdisposed on the power transmission route from the position where theengine side gear mechanism is arranged to the first motor side gearmechanism. With such the construction, the number of the clutches can bereduced from the conventional art, so the size of the vehicular powertransmission device can be reduced.

According to a second example aspect of the present invention, when theinput side clutch is disengaged, the power of the engine input shaft andthe power of the motor input shaft are enabled to be transmitted to theoutput shaft at different reduction gear ratios at the same time.

In this case, the rotation number of the motor can be made larger orsmaller than the rotation number of the engine since the rotation numberof the output shaft is the same.

According to a third example aspect of the present invention, areduction gear ratio of the engine side gear mechanism is smaller than areduction gear ratio of the first motor side gear mechanism.

With such the construction, the gear mechanism having the smallerreduction gear ratio than the motor is provided on the engine side.Therefore, the engine can use the gear mechanism having the smallreduction gear ratio, which is frequently used by the engine in thehybrid vehicle in general, irrespective of the engagement/disengagementof the input side clutch. The motor can use the gear mechanism havingthe large reduction gear ratio, which is frequently used by the motor inthe hybrid vehicle in general, irrespective of theengagement/disengagement of the input side clutch.

According to a fourth example aspect of the present invention, areduction gear ratio of the engine side gear mechanism is the smallestamong reduction gear ratios of gear mechanisms provided to the vehicularpower transmission device. A reduction gear ratio of the first motorside gear mechanism is the largest among the reduction gear ratios ofthe gear mechanisms provided to the vehicular power transmission device.

With such the construction, the gear mechanism having the smallestreduction gear ratio is provided on the engine side, and the gearmechanism having the largest reduction gear ratio is provided on themotor side. Therefore, the engine can use the gear mechanism, which isfrequently used by the engine in the hybrid vehicle in general,irrespective of the engagement/disengagement of the input side clutch.The motor can use the gear mechanism, which is frequently used by themotor in the hybrid vehicle in general, irrespective of theengagement/disengagement of the input side clutch.

According to a fifth example aspect of the present invention, thevehicular power transmission device further has a second motor side gearmechanism provided to the motor input shaft for transmitting the powerof the motor input shaft to the output shaft not through the engineinput shaft. A reduction gear ratio of the first motor side gearmechanism and a reduction gear ratio of the second motor side gearmechanism are larger than a reduction gear ratio of the engine side gearmechanism.

With such the construction, the engine can use the gear mechanism, whichis frequently used by the engine in the hybrid vehicle in general,irrespective of the engagement/disengagement of the input side clutch.The motor can use the first or second motor side gear mechanism, whichis frequently used by the motor in the hybrid vehicle in general,irrespective of the engagement/disengagement of the input side clutch.

According to a sixth example aspect of the present invention, the engineside gear mechanism is arranged between the first motor side gearmechanism and the engine.

In the power transmission device shown in FIG. 1 of Patent document 1,the first output shaft 33 is folded back at the clutch 36 toward theengine 51 side, and the second output shaft 34 is folded back at theclutch 37 toward the engine 51 side. Thus, the engine input shaft 32,the first output shaft 33 and the second output shaft 34 are formed as acoaxial three-layer structure.

However, in order to form the three-layer structure folded back at theclutches 36, 37 in this way, it is necessary to lengthen the engineinput shaft 32 transmitting the power of the engine 51. As a result, anexcessive mounting space is required and also resistance of the inputshaft 32 against a torsional vibration lowers.

Therefore, according to the above-described sixth aspect of the presentinvention, the engine side gear mechanism is arranged between the firstmotor side gear mechanism and the engine. Thus, the distance from theengine to the engine side gear mechanism can be shortened. As a result,the mounting space can be reduced and the resistance of the engine inputshaft against the torsional vibration can be maintained high.

According to a seventh example aspect of the present invention, in thevehicular power transmission device of the sixth example aspect of thepresent invention, the input side clutch is arranged between the engineside gear mechanism and the first motor side gear mechanism.

According to an eighth example aspect of the present invention, in thevehicular power transmission device of the sixth example aspect of thepresent invention, the input side clutch is arranged between the motorand the first motor side gear mechanism. The motor input shaft includesa cylindrical motor input shaft fixed to a portion of the input sideclutch that rotates with the motor input shaft. The cylindrical motorinput shaft coaxially surrounds another portion of the input side clutchthat rotates with the engine input shaft and extends toward the engineto coaxially surround the engine input shaft. The cylindrical motorinput shaft is structured to rotate with the other part of the motorinput shaft. The first motor side gear mechanism is fixed to an endportion of the cylindrical motor input shaft closer to the enginebetween two end portions of the cylindrical motor input shaft.

With such the construction, the engine input shaft is supported by thecylindrical motor input shaft rotatably, and the cylindrical motor inputshaft is supported by the engine input shaft rotatably. Therefore, thenumber of bearing members, which are provided separately for supportingthe engine input shaft and the motor input shaft, can be small. Also,since the input side clutch is not arranged between the engine side gearmechanism and the first motor side gear mechanism, the unit consistingof the engine side gear mechanism and the first motor side gearmechanism can be made compact.

According to a ninth example aspect of the present invention, in thevehicular power transmission device of the sixth example aspect of thepresent invention, the input side clutch is arranged between the engineand the engine side gear mechanism. The engine input shaft includes acylindrical engine input shaft fixed to a portion of the input sideclutch that rotates with the engine input shaft. The cylindrical engineinput shaft coaxially surrounds another portion of the input side clutchthat rotates with the motor input shaft and extends toward the motor tocoaxially surround the motor input shaft. The cylindrical engine inputshaft is structured to rotate with the other part of the engine inputshaft. The engine side gear mechanism is fixed to an end portion of thecylindrical engine input shaft closer to the motor between two endportions of the cylindrical engine input shaft.

With such the construction, the motor input shaft is supported by thecylindrical engine input shaft rotatably, and the cylindrical engineinput shaft is supported by the motor input shaft rotatably. Therefore,the number of bearing members, which are provided separately forsupporting the engine input shaft and the motor input shaft, can besmall. Also, since the input side clutch is not arranged between theengine side gear mechanism and the first motor side gear mechanism, theunit consisting of the engine side gear mechanism and the first motorside gear mechanism can be made compact.

According to a tenth example aspect of the present invention, the motoris arranged between the engine and the first motor side gear mechanism.The engine side gear mechanism is arranged on a farther side of thefirst motor side gear mechanism from the engine.

With such the construction, the motor can be arranged in a space, inwhich a clutch, a torque converter and the like have been placed in aconventional vehicle. Thus, the space can be used effectively.

According to an eleventh example aspect of the present invention, in thevehicular power transmission device of the tenth example aspect of thepresent invention, the input side clutch is arranged between the motorand the engine.

According to a twelfth example aspect of the present invention, in thevehicular power transmission device of the tenth example aspect of thepresent invention, the input side clutch is arranged between the engineside gear mechanism and the first motor side gear mechanism.

According to a thirteenth example aspect of the present invention, theinput side clutch is a clutch that transmits driving torque only fromthe engine input shaft side to the motor input shaft side. A reductiongear ratio of the motor side gear mechanism is larger than a reductiongear ratio of the engine side gear mechanism.

By adopting such a one-way clutch, it becomes unnecessary to control theengagement/disengagement of the input side clutch by using an actuator.As a result, it becomes unnecessary to provide the actuator. It isbecause the reduction gear ratio of the motor side gear mechanism islarger than the reduction gear ratio of the engine side gear mechanism.

According to a fourteenth example aspect of the present invention, thevehicular power transmission device further has a controller forcontrolling transmission routes and reduction gear ratios of the powersgenerated by the engine and the motor by controlling theengagement/disengagement of the input side clutch, the motor side gearmechanism and the engine side gear mechanism based on a physicalquantity obtained within the vehicle. The controller selects operationmodes of the engine and the motor allotted to the obtained physicalquantity based on a predetermined switching map that allots theoperation modes to a value of the physical quantity. The controllerrealizes the selected operation modes by controlling theengagement/disengagement of the input side clutch, the motor side gearmechanism and the engine side gear mechanism.

In this way, the switching map is used when the engagement/disengagementof the input side clutch, the motor side gear mechanism and the engineside gear mechanism is controlled to realize the decided operationmodes. Thus, predetermined running providing good efficiency can berealized.

According to a fifteenth example aspect of the present invention, in thevehicular power transmission device of the fourteenth example aspect ofthe present invention, the motor rotates using an electric power of abattery mounted to the vehicle for driving the vehicle. The controllerstores a plurality of kinds of switching maps beforehand. The controllerobtains SOC, or a state of charge, of the vehicle driving battery. Thecontroller selects one of the plurality of kinds of switching maps basedon the obtained SOC.

With such the construction, the efficient running corresponding to theSOC of the vehicle driving battery can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of embodiments will be appreciated, as well asmethods of operation and the function of the related parts, from a studyof the following detailed description, the appended claims, and thedrawings, all of which form a part of this application. In the drawings:

FIG. 1 is a skeleton diagram showing a construction of a vehicular powertransmission device according to a first embodiment of the presentinvention;

FIG. 2 is a diagram showing an input-output relation of a controlleraccording to the first embodiment;

FIG. 3 is a diagram showing a power transmission route during a MG1(L)mode according to the first embodiment;

FIG. 4 is a diagram showing a power transmission route during a MG1(H)mode according to the first embodiment;

FIG. 5 is a diagram showing a power transmission route during an ENG(L)mode according to the first embodiment;

FIG. 6 is a diagram showing a power transmission route during an ENG(H)mode according to the first embodiment;

FIG. 7 is a diagram showing a power transmission route during a powergeneration mode according to the first embodiment;

FIG. 8 is a graph showing characteristics of motors and an engineaccording to the first embodiment;

FIG. 9 is a diagram showing a switching map in an EV main mode accordingto the first embodiment;

FIG. 10 is a diagram showing a switching map in an engine main modeaccording to the first embodiment;

FIG. 11 is a flowchart showing processing executed by the controlleraccording to the first embodiment;

FIG. 12 is a block diagram showing processing for selecting an operationmode according to the first embodiment;

FIG. 13 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a second embodiment of thepresent invention;

FIG. 14 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a third embodiment of the presentinvention;

FIG. 15 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a fourth embodiment of thepresent invention;

FIG. 16 is a diagram showing relationships between operation modes andcontrol of clutches according to the fourth embodiment;

FIG. 17 is a graph showing characteristics of a motor and an engineaccording to the fourth embodiment;

FIG. 18 is a diagram showing a switching map in an EV main modeaccording to the fourth embodiment;

FIG. 19 is a diagram showing a switching map in an engine main modeaccording to the fourth embodiment;

FIG. 20 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a fifth embodiment of the presentinvention;

FIG. 21 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a sixth embodiment of the presentinvention;

FIG. 22 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a seventh embodiment of thepresent invention;

FIG. 23 is a skeleton diagram showing a construction of a vehicularpower transmission device according to an eighth embodiment of thepresent invention;

FIG. 24 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a ninth embodiment of the presentinvention;

FIG. 25 is a skeleton diagram showing a construction of a vehicularpower transmission device according to a tenth embodiment of the presentinvention;

FIG. 26 is a diagram showing a switching map in an engine main modeaccording to an eleventh embodiment of the present invention; and

FIG. 27 is a diagram showing a switching map in an engine main modeaccording to a twelfth embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENT First Embodiment

Hereinafter, a first embodiment of the present invention will bedescribed with reference to the drawings. FIG. 1 is a skeleton diagramshowing a construction of a vehicular power transmission deviceaccording to the first embodiment. The vehicular power transmissiondevice according to the present embodiment is mounted to a hybridvehicle. The vehicular power transmission device has an engine 1, motorsMG1, MG2, a first engine input shaft 2, a damper 3, a second engineinput shaft 4, a first drive gear 5, a first motor input shaft 6, asecond drive gear 7, an input side clutch 8, an output shaft 9, a firstdriven gear 10, a first output side clutch 11, a second driven gear 12,a second output side clutch 13, and a differential gear 14. Thevehicular power transmission device transmits powers (i.e., drivingtorque) generated by the engine 1 and the motors MG1, MG2 to an axle 15,thereby generating driving forces in driving wheels 16, 17.

The engine 1 is an internal combustion engine. The motors MG1, MG2 areelectric motors rotated by an electric power of a battery mounted to thevehicle for driving the vehicle (i.e., vehicle driving battery (notshown)). At the same time, the motors MG1, MG2 are generators thatgenerate the electric power by using axial torque transmitted from thevehicular power transmission device (more specifically, first motorinput shaft 6 for motor MG1, and output shaft 9 for motor MG2) andcharge the vehicle driving battery.

The power generated by the engine 1 is inputted to the first engineinput shaft 2 extending from the engine 1. The first engine input shaft2 functions as a shaft for transmitting the power inputted from theengine 1. The well-known torsion damper 3 is fixed to an end portion ofthe first engine input shaft 2 on a side opposite from the engine 1.

The second engine input shaft 4 is fixed to a side of the damper 3opposite to the first engine input shaft 2 coaxially with the firstengine input shaft 2. Therefore, the second engine input shaft 4 isstructured to transmit the power of the first engine input shaft 2through the damper 3.

The first drive gear 5 is pivotally fixed to the second engine inputshaft 4 such that the first drive gear 5 can rotate with the secondengine input shaft 4.

The power generated by the motor MG1 is inputted to the first motorinput shaft 6 extending from the motor MG1. The first motor input shaft6 functions as a shaft for transmitting the power inputted from themotor MG1.

The second drive gear 7 is pivotally fixed to the first motor inputshaft 6 such that the second drive gear 7 can rotate with the firstmotor input shaft 6.

The second engine input shaft 4 and the first motor input shaft 6 arearranged to be parallel and coaxial to each other. The input side clutch8 is a clutch mechanism arranged between the second engine input shaft 4and the first motor input shaft 6 for engaging/disengaging the secondengine input shaft 4 and the first motor input shaft 6 coaxially. A wetclutch or a dry clutch may be used as the input side clutch 8.

The power generated by the motor MG2 is inputted to the output shaft 9extending from the motor MG2. The output shaft 9 is arranged to belateral and parallel to the first engine input shaft 2, the secondengine input shaft 4 and the first motor input shaft 6. The output shaft9 outputs the power to be transmitted to the differential gear 14, theaxle 15 and the like.

The first driven gear 10 meshes with the first drive gear 5 and issupported by the output shaft 9 rotatably. The first output side clutch11 is a clutch mechanism fixed to the output shaft 9 forengaging/disengaging the output shaft 9 and the first driven gear 10. Awet clutch or a dry clutch may be used as the first output side clutch11. Alternatively, a meshing clutch such as a synchronization mechanismmay be employed as the first output side clutch 11.

The second driven gear 12 meshes with the second drive gear 7 and issupported by the output shaft 9 rotatably. The second output side clutch13 is a clutch mechanism fixed to the output shaft 9 forengaging/disengaging the output shaft 9 and the second driven gear 12. Awet clutch or a dry clutch may be used as the second output side clutch13. Alternatively, a meshing clutch such as a synchronization mechanismmay be employed as the second output side clutch 13.

The power of the output shaft 9 is transmitted to the driving wheels 16,17 through a final gear (not shown), the differential gear 14 and theaxle 15.

In the vehicular power transmission device having the above-describedconstruction, if the first output side clutch 11 is engaged, the powertransmission is performed between the output shaft 9 and the firstdriven gear 10. Therefore, the power transmission is performed betweenthe second engine input shaft 4 and the output shaft 9 through the firstdrive gear 5, the first driven gear 10 and the first output side clutch11 (not through first motor input shaft 6). If the first output sideclutch 11 is disengaged, the power transmission between the secondengine input shaft 4 and the output shaft 9 through the first drive gear5, the first driven gear 10 and the first output side clutch 11 is notperformed. The first drive gear 5, the first driven gear 10 and thefirst output side clutch 11 constitute a high gear mechanism(corresponding to example of engine side gear mechanism). A reductiongear ratio of the high gear mechanism is the smallest among reductiongear ratios of gear mechanisms provided to the vehicular powertransmission device.

If the second output side clutch 13 is engaged, the power transmissionis performed between the output shaft 9 and the second driven gear 12.Therefore, the power transmission is performed between the first motorinput shaft 6 and the output shaft 9 through the second drive gear 7,the second driven gear 12 and the second output side clutch 13 (notthrough engine input shafts 2, 4). If the second output side clutch 13is disengaged, the power transmission between the first motor inputshaft 6 and the output shaft 9 through the second drive gear 7, thesecond driven gear 12 and the second output side clutch 13 is notperformed. The second drive gear 7, the second driven gear 12 and thesecond output side clutch 13 constitute a low gear mechanism(corresponding example of first motor side gear mechanism). A reductiongear ratio of the low gear mechanism is the largest among the reductiongear ratios of the gear mechanisms provided to the vehicular powertransmission device. Therefore, the reduction gear ratio of the low gearmechanism is larger than the reduction gear ratio of the high gearmechanism.

In this way, in the vehicular power transmission device, the gearmechanism closer to the engine 1 is the high gear mechanism and the gearmechanism closer to the motor MG1 is the low gear mechanism in terms ofboth of the power transmission route and the arrangement.

If the input side clutch 8 is engaged, the power is transmitted betweenthe second engine input shaft 4 and the first motor input shaft 6through the input side clutch 8. If the input side clutch 8 isdisengaged, the power transmission between the second engine input shaft4 and the first motor input shaft 6 through the input side clutch 8 isnot performed.

If the input side clutch 8 is engaged, the power transmission isinvariably possible from a position where the first drive gear 5 isarranged on the second engine input shaft 4 to a position where thesecond drive gear 7 is arranged on the first motor input shaft 6. Inother words, there is no clutch other than the input side clutch 8 onthe power transmission route on the input shafts 2, 4, 6 from theposition where the first drive gear 5 is provided to the second drivegear 7. With such the construction, the number of the clutches can bereduced from conventional arts, so the size of the vehicular powertransmission device can be reduced.

By arranging the input side clutch 8 and the first drive gear 5 in thepositions between the second drive gear 7 and the engine 1, the distancefrom the engine 1 to the first drive gear 5 can be reduced. As a result,resistance of the engine input shafts 2, 4 against a torsional vibrationcan be maintained high.

By arranging the input side clutch 8 and the second drive gear 7 in thepositions between the first drive gear 5 and the motor MG1, the distancefrom the motor MG1 to the second drive gear 7 can be reduced. As aresult, resistance of the first motor input shaft 6 against thetorsional vibration can be maintained high.

The engine side gear mechanism 5, 10, 11 is structured to transmit thepower from a certain position on the power transmission route, whichextends from the engine 1 to the input side clutch 8 along the engineinput shafts 2, 4, to the output shaft 9. Therefore, there is no need todivide the power transmission route of the engine 1 into two routes of aroute from the engine 1 to the first drive gear 5 and a route from theengine 1 to the second drive gear 7 as in Patent document 1.Accordingly, the construction is simplified.

The vehicular power transmission device has a controller 20(transmission controller). The controller 20 controlsdriving/non-driving of the above-mentioned motors MG1, MG2 andengagement/disengagement of the input side clutch 8, the first outputside clutch 11 and the second output side clutch 13 based on variousphysical quantities obtained within the vehicle. Thus, the controller 20controls the transmission routes and the reduction gear ratios of thepowers generated by the engine 1 and the motor MG1. An electroniccontroller having a microcontroller, which executes programs, is used asthe controller 20, for example.

More specifically, as shown in FIG. 2, the controller 20 receives inputsof a vehicle speed signal indicating running speed of the vehicle, anaccelerator position signal indicating an accelerator position, a SOCsignal indicating SOC (State Of Charge) showing a charging rate of thevehicle driving battery and the like. As the vehicle speed signal, asignal outputted from a wheel speed sensor mounted to each wheel isused, for example. As the accelerator position signal, a signaloutputted from an accelerator position sensor is used, for example. Asthe SOC signal, a signal outputted from a battery monitoring device thatsenses and outputs the SOC of the vehicle driving battery is used.

The controller 20 switches between the engagement and the disengagementof the above-mentioned input side clutch 8, the first output side clutch11 and the second output side clutch 13 based on the above-mentionedinputted signals. More specifically, the controller 20 switches betweenthe engagement and the disengagement of the clutches 8, 11, 13 bycontrolling operations of actuators provided for the clutches 8, 11, 13respectively for realizing corresponding engagement and disengagement(for example, actuators for generating oil pressure forengaging/disengaging clutches).

Such the control of the clutches 8, 11, 13 by the controller 20 enablesboth of the transmission of the power generated by the motor MG1 to thedriving wheels 16, 17 through the low gear mechanism and thetransmission of the power generated by the motor MG1 to the drivingwheels 16, 17 through the high gear mechanism. Also the power generatedby the engine 1 can be transmitted to the driving wheels 16, 17 throughthe low gear mechanism and can be transmitted to the driving wheels 16,17 through the high gear mechanism.

For example, in a MG1(L) mode shown in FIG. 3, the power of the motorMG1 is transmitted to the driving wheels 16, 17 through the low gearmechanism along a route shown by an arrow mark 23. In this mode, thesecond output side clutch 13 is engaged and the engagement/disengagementof the other clutches 8, 11 is arbitrary. However, all of the clutches8, 11, 13 are not engaged at the same time.

In a MG1(H) mode shown in FIG. 4, the power of the motor MG1 istransmitted to the driving wheels 16, 17 through the high gear mechanismalong a route shown by an arrow mark 24. In this mode, the input sideclutch 8 and the first output side clutch 11 are engaged respectively,and the second output side clutch 13 is disengaged.

In an ENG(L) mode shown in FIG. 5, the power of the engine 1 istransmitted to the driving wheels 16, 17 through the low gear mechanismalong a route shown by an arrow mark 25. In this mode, the input sideclutch 8 and the second output side clutch 13 are engaged respectively,and the first output side clutch 11 is disengaged.

In an ENG(H) mode shown in FIG. 6, the power of the engine 1 istransmitted to the driving wheels 16, 17 through the high gear mechanismalong a route shown by an arrow mark 26. In this mode, the first outputside clutch 11 is engaged, and the engagement/disengagement of the otherclutches 8, 13 is arbitrary. However, all the clutches 8, 11, 13 are notengaged at the same time.

In an electric power generation mode shown in FIG. 7, the power of theengine 1 is transmitted to the motor MG1 through the input side clutch 8along a route shown by an arrow mark 27. In this mode, the input sideclutch 8 is engaged, and the other clutches 11, 13 are disengaged. Inthe electric power generation mode, the motor MG1 generates an electricpower by using the power of the engine 1 and can charge the drivingbattery. Such the mode can be realized when the vehicle stops. Such themode can be realized also when the vehicle runs at low speed using thepower generated by the motor MG2. Also, in-series operation for runningthe vehicle with the motor MG2 by using the electric power generated bythe motor MG1 can be realized.

The above-mentioned driving modes of the motor MG1 (MG1(L) mode, MG1(H)mode) and the driving modes of the engine 1 (ENG(L) mode, ENG(H) mode)can be combined.

For example, when both of the motor MG1 and the engine 1 use the lowgear mechanism, the above-mentioned MG1(L) mode and ENG(L) mode may becombined such that the input side clutch 8 and the second output sideclutch 13 are engaged respectively, and the first output side clutch 11is disengaged.

For example, when both of the motor MG1 and the engine 1 use the highgear mechanism, the above-mentioned MG1(H) mode and ENG(H) mode may becombined such that the input side clutch 8 and the first output sideclutch 11 are engaged respectively, and the second output side clutch 13is disengaged.

When the motor MG1 uses the low gear mechanism and the engine 1 uses thehigh gear mechanism, the above-mentioned MG1(L) mode and ENG(H) mode maybe combined such that the first output side clutch 11 and the secondoutput side clutch 13 are engaged respectively, and the input sideclutch 8 is disengaged. In this way, different reduction gear ratios canbe realized between the engine 1 and the motor MG1 at the same time. Inthis case, since the rotation speed of the output shaft 9 is the same,the rotation speed of the motor MG1 can be made larger than the rotationspeed of the engine 1. Thus, operating points of the respective drivingsources providing high efficiency respectively can be selected.

However, the clutches 8, 11, 13 cannot be controlled such that the motorMG1 uses the high gear mechanism and the engine 1 uses the low gearmechanism respectively. As explained in detail with reference to FIG. 8,a situation where the motor MG1 provides high efficiency by using thehigh gear mechanism is totally different from a situation where theengine 1 provides high efficiency by using the low gear mechanism.Therefore, even if these two situations cannot be realized at the sametime, an adverse effect to a gas mileage of the vehicle is small.

The controller 20 is configured to realize the running suitable for thestate of the vehicle by controlling the driving and non-driving of themotors MG1, MG2 in addition to the combination of the engagement and thedisengagement of the clutches 8, 11, 13.

By combining the combination of the engagement and disengagement of theclutches 8, 11, 13 and the driving and non-driving of the motors MG1,MG2, the operation mode of the motor MG1 includes a non-driving mode fornot transmitting the power to the output shaft 9, the MG1(L) mode, andthe MG1(H) mode. The operation mode of the motor MG2 includes anon-driving mode for not generating the power and a driving mode forgenerating the power and inputting the power into the output shaft 9.The operation mode of the engine 1 includes a non-driving mode for nottransmitting the power to the output shaft 9, the ENG(L) mode and theENG(H) mode. The operation modes of the motors MG1, MG2 and the engine 1can be combined except for certain combinations among them.

In order to explain the running suitable for the state of the vehicle,an example of characteristics of the motors MG1, MG2 and the engine 1 isshown in FIG. 8 as a graph.

In FIG. 8, a horizontal axis is vehicle speed and a vertical axis isdriving torque of the axle 15. A solid line 30 shows necessary drivingtorque at respective vehicle speeds during flat-area constant-speedrunning, which is running on a flat area at constant speed. A solid line31 shows an upper limit of the driving torque, which the motor MG1 canoutput (generate) at respective vehicle speeds in the MG1(L) mode. Asolid line 32 shows an upper limit of the driving torque, which themotor MG1 can output (generate) at respective vehicle speeds in theMG1(H) mode. A solid line 33 shows an upper limit of the driving torque,which the motor MG2 can output (generate) at respective vehicle speeds.

An area 34 surrounded by a broken line shows an area where efficiency(equivalent to gas mileage) in the MG1(L) mode is assumed to be equal toor higher than a predetermined reference. An area 35 surrounded by abroken line shows an area where efficiency (equivalent to gas mileage)in the MG1(H) mode is assumed to be equal to or higher than apredetermined reference. An area 36 surrounded by a broken line shows anarea where efficiency in the driving mode of the motor MG2 is assumed tobe equal to or higher than a predetermined reference. A solid line 37shows a range (maximum efficiency line) in which the efficiency isassumed to be the maximum in the ENG(L) mode. A solid line 38 shows arange (maximum efficiency line) in which the efficiency is assumed to bethe maximum in the ENG(H) mode.

A basic concept of the selection of the operation modes of the motorsMG1, MG2 and the engine 1 is as follows. That is, when the necessarydriving torque can be realized only by the motor MG2, the vehicle isdriven only by the motor MG2. In the other cases, the most efficientcombination is selected in the relationship between the vehicle speedand the necessary driving torque.

Typically, in an area 39 a from start to low-speed or middle-speedacceleration where the vehicle speed ranges from 0 km/h to approximately60 km/h, the MG1(L) mode and the ENG(L) mode having the high efficiencyarea 34 and range 37 in the area 39 a are used positively. In an area 39b of high-speed acceleration or hill-climbing where the vehicle speedranges from approximately 60 km/h to approximately 150 km/h, the MG1(H)mode, the driving mode of the motor MG2 and the ENG(H) mode having thehigh efficiency areas 35, 36 and range 38 in or near the area 39 b areused positively.

Next, flat-area constant-speed running in an EV main mode for drivingthe vehicle mainly with the motors MG1, MG2 will be explained as anexample. The EV main mode is a running mode used when the SOC of thevehicle driving battery has a margin.

In the EV main mode, when the vehicle speed is lower than 130 km/hduring the flat-area constant-speed running, the necessary drivingtorque is lower than the maximum driving torque of the motor MG2.Therefore, the running can be realized only with the power of motor MG2.That is, the motor MG1 and the engine 1 are brought to the non-drivingmodes, and the motor MG2 is brought to the driving mode. In order to doso, the controller 20 disengages all the clutches 8, 11, 13 and stopsthe motor MG1. At that time, since the motor MG1 can be stoppedcompletely, loss due to dragged rotation of the motor MG1 can bereduced.

Even during the flat-area constant-speed running, when the vehicle speedexceeds 130 km/h, necessary driving torque cannot be covered only withthe power of the motor MG2. Therefore, the running is performed in amode for combining the ENG(H) mode and the MG1(H) mode and also fordriving the motor MG2.

Next, as another example, flat-area constant-speed running in an enginemain mode for driving the vehicle mainly with the engine 1 will beexplained. The engine main mode is a running mode used when the SOC ofthe vehicle driving battery does not have the margin.

In the engine main mode, during the flat-area constant-speed running, inorder to save the electric power of the vehicle driving battery, thedriving mode of the motor MG2 and the ENG(H) mode are combined, andfurther, the non-driving mode of the motor MG1 is combined. In order todo so, the controller 20 engages the first output side clutch 11,disengages the clutches 8, 13 respectively, and stops the motor MG1. Atthat time, since the motor MG1 can be stopped completely, loss due tothe dragged rotation of the motor MG1 can be reduced.

In order to efficiently utilize the characteristics of the motors MG1,MG2 and the engine 1 as shown in FIG. 8 in this way, a switching map inthe EV main mode as shown in FIG. 9 and a switching map in the enginemain mode as shown in FIG. 10 are stored in a storage medium (such asROM or flash memory) of the controller 20 in advance (for example, infactory shipment).

The switching map shown in FIG. 9 is a data that partitions atwo-dimensional plane defined by the vehicle speed and the drivingtorque into multiple blocks 41-47 and that allots a set of combinationof the operation modes of the motors MG1, MG2 and the engine 1 to eachof blocks 41-47 respectively. The switching map shown in FIG. 10 is adata that partitions a two-dimensional plane defined by the vehiclespeed and the driving torque into multiple blocks 51-54 and that allotsa set of combination of the operation modes of the motors MG1, MG2 andthe engine 1 to each of blocks 51-54 respectively. In short, eachswitching map is a data that allots a set of the combination of theoperation modes to the combination of the vehicle speed and the drivingtorque.

The controller 20 reads and executes a predetermined program to performrunning mode switching processing as shown in FIG. 11 in eachpredetermined control cycle. Thus, the controller 20 switches the EVmain mode and the engine main mode alternately.

More specifically, in each control cycle, first in S105 (S means“Step”), a present running mode is obtained by reading a running modevariable in a storage medium such as RAM. Then, in S110, a present SOCof the vehicle driving battery is obtained. In following S115, it isdetermined whether the running mode obtained in S105 is the EV mainmode. If the present running mode is the EV main mode, S120 is executedsubsequently. If the running mode is not the EV main mode (i.e., ifrunning mode is engine main mode), S140 is executed subsequently.

In S120, it is determined whether the present SOC is lower than apredetermined EV running lower limit value. If the present SOC is notlower than the EV running lower limit value, the process proceeds toS125 subsequently. In S125, the running mode is maintained in the EVmain mode by not rewriting the above-mentioned running mode variable.Then, the present running mode switching processing is ended. If it isdetermined that the present SOC is lower than the EV running lower limitvalue in S120, the running mode is switched to the engine main mode inS130 subsequently. In this case, a value representing the engine mainmode is assigned to the running mode variable, and the present runningmode switching processing is ended.

In S140, it is determined whether the present SOC is lower than apredetermined engine running upper limit value. If the present SOC islower than the engine running upper limit value, the process proceeds toS145 subsequently. In order to provide hysteresis, the engine runningupper limit value is set at a value larger than the EV running lowerlimit value. In S145, the running mode is maintained in the engine mainmode by not rewriting the above-mentioned running mode variable. Then,the present running mode switching processing is ended. If it isdetermined that the SOC is not lower than the engine running upper limitvalue in S140, the running mode is switched to the EV main mode in S150subsequently. In this case, a value representing the EV main mode isassigned to the above-mentioned running mode variable, and the presentrunning mode switching processing is ended.

By the repetition of such the processing by the controller 20, while therunning mode is the EV main mode and the SOC does not fall below the EVrunning lower limit value, the processing is performed in the order ofS105, S110, S115, S120 and S125. Thus, the running mode is maintained inthe EV main mode. If the SOC gradually decreases due to the use of themotors MG1, MG2 and falls below the EV running lower limit value, theprocessing is performed in the order of S105, S110, S115, S120 and S130.Thus, the running mode switches from the EV main mode to the engine mainmode.

While the running mode is the engine main mode and the SOC is lower thanthe engine running upper limit value, the processing is performed in theorder of S105, S110, S115, S140 and S145, so the running mode ismaintained in the engine main mode. If the SOC gradually increases dueto the electric power generation and the like and becomes equal to orhigher than the engine running upper limit value, the processing isperformed in the order of S105, S110, S115, S140 and S150, so therunning mode switches from the engine main mode to the EV main mode.

The controller 20 executes a predetermined program to obtain the currentaccelerator position and the current vehicle speed in each predeterminedcontrol cycle as shown in FIG. 12. The controller 20 selects theoperation modes of the motors MG1, MG2 and the engine 1 based on theobtained accelerator position and vehicle speed. More specifically, thecontroller 20 calculates the necessary driving torque from the obtainedaccelerator position according to an accelerator position-torque map 21beforehand stored in a storage medium (such as ROM or flash memory) ofthe controller 20. The accelerator position-torque map 21 is a datashowing a correspondence relationship between the accelerator positionand the driving torque necessary for the accelerator position.

The controller 20 selects a combination of the operation modes of themotors MG1, MG2 and the engine 1 corresponding to the calculated drivingtorque and the obtained vehicle speed based on the switching map 22shown in FIG. 9 or 10.

More specifically, the switching map corresponding to the presentrunning mode is used, and the block including the position of thecombination of the calculated driving torque and the obtained vehiclespeed is read from the switching map. Then, the combination of theoperation modes of the motors MG1, MG2 and the engine 1 allotted to theblock is selected.

Next, concrete contents of the block partitioning and the allotment ofthe switching maps shown in FIGS. 9 and 10 will be explained. In theswitching map for the EV main mode of FIG. 9, a range of the drivingtorque equal to or lower than approximately 200 Nm provides a singleblock 41 across the entire vehicle speed range. A combination of thedriving mode of the MG2, the non-driving mode of the motor MG1 and thenon-driving mode of the engine 1 is allotted to the block 41. Thiscombination is realized by disengaging the input side clutch 8, thefirst output side clutch 11 and the second output side clutch 13respectively.

A block 42 covering a driving torque range immediately above the block41 is defined in the range from start to low-speed or middle-speedacceleration ranging from 0 km/h to approximately 60 km/h. A combinationof the MG1(L) mode, the non-driving mode of the motor MG2 and thenon-driving mode of the engine 1 is allotted to the block 42. Thiscombination is realized by disengaging the input side clutch 8 and thefirst output side clutch 11 respectively, by engaging the second outputside clutch 13, and by idling the motor MG2 with the rotation of theoutput shaft 9 without driving the motor MG2. By doing so, theefficiency can be improved since the block 42 includes the highefficiency area 34 of the MG1(L) mode shown in FIG. 8.

A block 43 covering a driving torque range immediately above the block42 is defined in the range from start to low-speed or middle-speedacceleration ranging from 0 km/h to approximately 60 km/h. A combinationof the MG1(L) mode, the driving mode of the motor MG2 and thenon-driving mode of the engine 1 is allotted to the block 43. Thiscombination is realized by disengaging the input side clutch 8 and thefirst output side clutch 11 and by engaging the second output sideclutch 13 respectively. By using the motors MG1, MG2 together in thisway, while the power generated by the motor MG1 is the driving torque inor near the high efficiency area 34 of the MG1(L) mode shown in FIG. 8,the driving torque of the axle 15 larger than the high efficiency area34 can be realized.

A block 44 covering a driving torque range immediately above the block43 is defined in a vehicle speed range from 20 km/h to approximately 60km/h. A combination of the MG1(L) mode, the driving mode of the motorMG2 and the ENG(H) is allotted to the block 44. This combination isrealized by disengaging the input side clutch 8 and by engaging thefirst output side clutch 11 and the second output side clutch 13respectively. By using the motors MG1, MG2 and the engine 1 together inthis way, while the power generated by the motor MG1 is the drivingtorque in or near the high efficiency area 34 of the MG1(L) mode shownin FIG. 8 and the power generated by the engine 1 is the driving torquein or near the high efficiency range 38 of the ENG(H) mode shown in FIG.8, the driving torque of the axle 15 larger than the high efficiencyarea 34 or range 38 can be realized.

Since the gear mechanisms used by the motor MG1 and the engine 1 can bedifferentiated from each other in this way, the range of selection ofthe operation modes can be widened. Specifically, as shown in FIG. 8,both the high efficiency area 34 of the MG1(L) mode and the highefficiency range 38 of the ENG(H) mode are included in the range 39 afrom start to low-speed or middle-speed acceleration where the vehiclespeed is approximately 60 km/h or lower. Thus, the two high efficiencyarea 34 and range 38 can be used in combination.

A block 45 covering a driving torque range immediately above the blocks43, 44 is defined in a range of the vehicle speed from approximately 20km/h to approximately 60 km/h. A combination of the MG1(L) mode, thedriving mode of the motor MG2 and the ENG(L) mode is allotted to theblock 45. This combination is realized by engaging the input side clutch8 and the second output side clutch 13 and by disengaging the firstoutput side clutch 11 respectively. By using the motors MG1, MG2 and theengine 1 together in this way, while the power generated by the motorMG1 is the driving torque in or near the high efficiency area 34 of theMG1(L) mode shown in FIG. 8 and the power generated by the engine 1 isthe driving torque in or near the high efficiency range 37 of the ENG(L)mode shown in FIG. 8, the driving torque of the axle 15 larger than thehigh efficiency area 34 or range 37 can be realized. Since the ENG(L)mode is used unlike the area 44, larger driving torque can be realizedefficiently.

A block 46 covering a driving torque range immediately above the block41 is defined in a range over approximately 60 km/h. A combination ofthe MG1 non-driving mode, the driving mode of the motor MG2 and theENG(H) mode is allotted to the block 46. This combination is realized bydisengaging the input side clutch 8 and the second output side clutch 13and by engaging the first output side clutch 11 respectively. By usingthe motor MG2 and the engine 1 together in this way, while the powergenerated by the motor MG2 is the driving torque in or near the highefficiency area 36 of the MG2 driving mode shown in FIG. 8 and the powergenerated by the engine 1 is the driving torque in or near the highefficiency range 38 of the ENG(H) mode shown in FIG. 8, the drivingtorque of the axle 15 larger than the high efficiency area 36 or range38 can be realized.

A block 47 covering a driving torque range immediately above the block46 is defined in a range from approximately 60 km/h to approximately 150km/h. A combination of the MG1(H) mode, the driving mode of the motorMG2 and the ENG(H) mode is allotted to the block 47. This combination isrealized by disengaging the second output side clutch 13 and by engagingthe input side clutch 8 and the first output side clutch 11respectively. By using the motors MG1, MG2 and the engine 1 together inthis way, while the power generated by the motor MG1 is the drivingtorque in or near the high efficiency area 35 of the MG1(H) mode shownin FIG. 8 and the power generated by the engine 1 is the driving torquein or near the high efficiency range 38 of the ENG(H) mode shown in FIG.8, the driving torque of the axle 15 larger than the high efficiencyarea 35 or range 38 can be realized.

In this way, in the EV main mode, in the range 39 a from start tolow-speed or middle-speed acceleration, the controller 20 selects thedriving source(s) in the MG2 single mode of the block 41, the MG1(L)single mode of the block 42, the MG1(L)+MG2 mode of the block 43, theMG1(L)+MG2+ENG(H) mode of the block 44, and the MG1(L)+MG2+ENG(L) modeof the block 45 in this order as the necessary driving torque increases.Also in the EV main mode, in the high-speed acceleration orhill-climbing range 39 b, the controller 20 selects the drivingsource(s) in the MG2 single mode of the block 41, the MG2+ENG(H) mode ofthe block 46, and the MG1(H)+MG2+ENG(H) mode of the block 47 in thisorder as the request torque increases.

In the EV main mode, the input side clutch 8 is engaged only in theblocks 45, 47, in which the engine 1 and the motor MG1 use the same gearmechanism. Therefore, the input side clutch 8 does not operate unlessthe necessary driving torque becomes very large. Therefore, wear of theinput side clutch 8 and friction plates of the input side clutch 8 canbe reduced significantly. At the same time, a driving energy of anactuator can be reduced significantly.

Next, the contents of the switching map for the engine main mode shownin FIG. 10 will be explained. Differently from the EV main mode, theengine 1 is invariably used in the engine main mode to suppress a suddenfall of the SOC of the vehicle driving battery.

In the switching map for the engine main mode shown in FIG. 10, an area,whose upper boundary driving torque ranges approximately from 200 to 300Nm, defines a single block 51 across the entire vehicle speed rangeexcept for a very low speed range (speed range lower than approximately15 km/h). A combination of the driving mode of the MG2, the non-drivingmode of the motor MG1 and the ENG(H) is allotted to the block 51. Thiscombination is realized by disengaging the input side clutch 8 and thesecond output side clutch 13 respectively, by engaging the first outputside clutch 11, and by stopping the motor MG1. At that time, since themotor MG1 can be stopped completely, loss due to dragged rotation of themotor MG1 can be reduced.

A block 52 is set to cover an area of the very low speed from 0 km/h toapproximately 15 km/h and the driving torque of approximately 400 Nm orlower and to cover a driving torque range immediately above the block 51in a range from start to low-speed or middle-speed acceleration rangingfrom approximately 15 km/h to approximately 60 km/h. A combination ofthe non-driving mode of the MG1, the driving mode of the motor MG2 andthe ENG(L) mode is allotted to the block 52. This combination isrealized by disengaging the first output side clutch 11, by engaging theinput side clutch 8 and the second output side clutch 13 respectively,and by idling the motor MG1 with the rotation of the first motor inputshaft 6 without driving the motor MG1. By doing so, the efficiency canbe heightened since the block 52 includes the high efficiency range 37of the ENG(L) mode shown in FIG. 8.

A block 53 covering a driving torque range immediately above the block52 is defined in a range from start to low-speed or middle-speedacceleration ranging from 0 km/h to approximately 60 km/h. A combinationof the MG1(L) mode, the driving mode of the MG2 and the ENG(L) mode isallotted to the block 53. This combination is realized by disengagingthe first output side clutch 11 and by engaging the input side clutch 8and the second output side clutch 13 respectively.

By using the motors MG1, MG2 and the engine 1 together in this way,while the power generated by the motor MG1 is the driving torque in ornear the high efficiency area 34 of the MG1(L) mode shown in FIG. 8,while the power generated by the motor MG2 is the driving torque in ornear the high efficiency area 36 of the driving mode of the MG2 shown inFIG. 8, and while the power generated by the engine 1 is the drivingtorque in or near the high efficiency range 37 in the ENG(L) mode shownin FIG. 8, the driving torque of the axle 15 larger than the highefficiency areas 34, 36 or range 37 can be realized. Since the MG1(L)mode is also used differently from the block 52, larger driving torquecan be realized efficiently.

A block 54 covering a driving torque range immediately above the block51 is defined in a range from approximately 60 km/h to approximately 150km/h. A combination of the MG1(H) mode, the driving mode of the motorMG2 and the ENG(H) mode is allotted to the block 54. This combination isrealized by disengaging the second output side clutch 13 and by engagingthe input side clutch 8 and the first output side clutch 11respectively.

By using the motors MG1, MG2 and the engine 1 together in this way,while the power generated by the motor MG1 is the driving torque in ornear the high efficiency area 35 of the MG1(H) mode shown in FIG. 8,while the power generated by the motor MG2 is the driving torque in ornear the high efficiency area 36 of the driving mode of the MG2 shown inFIG. 8, and while the power generated by the engine 1 is the drivingtorque in or near the high efficiency range 38 of the ENG(H) mode shownin FIG. 8, the driving torque of the axle 15 larger than the highefficiency areas 35, 36 or range 38 can be realized.

In this way, in the engine main mode, in the range of the very low speedlower than approximately 15 km/h, the controller 20 selects the drivingsources in the ENG(L)+MG2 mode of the block 52 and the MG1(L)+MG2+ENG(L)mode of the block 53 in this order as the necessary driving torqueincreases. Also in the engine main mode, in the range of approximately15 km/h or over in the low-speed or middle-speed acceleration range 39a, the controller 20 selects the driving sources in the ENG(H)+MG2 modeof the block 51, the ENG(L)+MG2 mode of the block 52, and theMG1(L)+MG2+ENG (L) mode of the block 53 in this order as the necessarydriving torque increases. Also in the engine main mode, in thehigh-speed acceleration or hill-climbing range 39 b, the controller 20selects the driving sources in the ENG(H)+MG2 mode of the block 51 andthe MG1(H)+MG2+ENG (H) mode of the block 54 in this order as the requesttorque increases.

As explained above, the controller 20 selectively uses the EV main modefor mainly using the motors MG1, MG2 or the engine main mode for mainlyusing the engine 1 according to the SOC of the vehicle driving battery.In each mode, the controller 20 selects the efficient combination fromthe combinations of the driving/non-driving and the reduction gearratios of the motors MG1, MG2 and the engine 1 according to thenecessary driving torque and the vehicle speed. In order to realize theselected combination, the controller 20 controls theengagement/disengagement of the input side clutch 8, the first outputside clutch 11 and the second output side clutch 13 and thedriving/non-driving of the motors MG1, MG2.

As shown in the switching maps of FIGS. 9 and 10, the ENG (H) mode isused more often than the ENG (L) mode and the MG1(L) mode is used moreoften than the MG1(H) mode in the area realized in the normal running(i.e., area of vehicle speed from 0 to 60 km/h and driving torque from 0to 300 Nm).

In this way, in order to enable the operation in the areas 34, 35 wherethe efficiency of the motor MG1 is high in the range where the runningspeed is high or middle and the running cannot be realized only with thepower of the motor MG1, the controller 20 switches theengagement/disengagement of the input side clutch 8, the first outputside clutch 11 and the second output side clutch 13 such that the powertransmission route of the motor MG1 can be selected between the highgear mechanism having the low reduction gear ratio and the low gearmechanism having the high reduction gear ratio.

When the running speed is high and the running can be performed onlywith the power of the engine 1, the controller 20 transmits the powersof the engine 1 and the motor MG2 to the driving wheels through the highgear mechanism, which is provided on the engine 1 side and which has thelow reduction gear ratio, without engaging the input side clutch 8.

When the running speed is low and the running can be performed only withthe power of the motor MG1, the controller 20 transmits the power of themotor MG1 to the driving wheels through the low gear mechanism, which isprovided on the motor MG1 side and which has the high reduction gearratio.

When the running speed is low and the running cannot be performed onlywith the power of the motor MG1, the controller 20 transmits the totalpower of the engine 1 and the motor MG1 to the axle 15 through the lowgear mechanism, which is provided on the motor MG1 side and which hasthe high reduction gear ratio, by engaging the input side clutch 8.

Since the vehicular power transmission device is structured as explainedabove, if the input side clutch 8 is engaged, the high gear mechanism 5,10, 11 on the engine side or the low gear mechanism 7, 12, 13 on themotor side can be used commonly by the engine 1 and the motor MG1. Ifthe input side clutch 8 is disengaged, the engine 1 can use the highgear mechanism 5, 10, 11 while the motor MG1 can use the low gearmechanism 7, 12, 13.

The high gear mechanism having the lowest reduction gear ratio isprovided on the engine 1 side, and the low gear mechanism having thehighest reduction gear ratio is provided on the motor MG1 side.Therefore, the engine 1 can use the gear mechanism, which is frequentlyused by the engine 1 in the hybrid vehicle in general, irrespective ofthe engagement/disengagement of the input side clutch 8. The motor MG1can use the gear mechanism, which is frequently used by the motor MG1 inthe hybrid vehicle in general, irrespective of theengagement/disengagement of the input side clutch 8.

Second Embodiment

Next, a second embodiment of the present invention will be described,focusing on differences from the first embodiment. As shown in FIG. 13,differently from the first embodiment, in the vehicular powertransmission device according to the present embodiment, the input sideclutch 8 that engages and disengages the first motor input shaft 6 andthe second engine input shaft 4 is arranged between the motor MG1 andthe second drive gear 7, not between the first drive gear 5 and thesecond drive gear 7.

In order to realize such the arrangement, a cylindrical motor inputshaft 18 is attached to a portion of the input side clutch 8 thatrotates with the first motor input shaft 6. The cylindrical motor inputshaft 18 coaxially surrounds another portion of the input side clutch 8that rotates with the second engine input shaft 4. The cylindrical motorinput shaft 18 coaxially surrounds the second engine input shaft 4 andextends toward the engine 1. The cylindrical motor input shaft 18rotates with the first motor input shaft 6. The second drive gear 7 isfixed not to the first motor input shaft 6 but to an end portion of thecylindrical motor input shaft 18 closer to the engine 1 between two endportions. The second drive gear 7 rotates with the cylindrical motorinput shaft 18.

In the present embodiment, the second engine input shaft 4 is supportedby the cylindrical motor input shaft 18 rotatably, and the cylindricalmotor input shaft 18 is supported by the second engine input shaft 4rotatably. Therefore, the number of bearings, which are separatelyprovided for supporting the input shafts 4, 6, 18, can be reduced ascompared to the vehicular power transmission device of the firstembodiment. Since the input side clutch 8 is not arranged between thelow gear mechanism and the high gear mechanism, the unit consisting ofthe low gear mechanism and the high gear mechanism can be made compact.

In the present embodiment, the engine 1, the engine input shafts 2, 4,the first drive gear 5, the second drive gear 7, the input side clutch8, the first motor input shaft 6 and the motor MG1 are arranged on thesame axis in this order. With such the arrangement, shaft length of thefirst motor input shaft 6 can be shortened, so resistance against thetorsional vibration increases.

The other construction and the operation of the controller 20 of thepresent embodiment are the same as those of the first embodiment.Therefore, like the first embodiment, the second engine input shaft 4that transmits the power from the engine 1 to the first drive gear 5 andthe first motor input shaft 6 that transmits the power from the motorMG1 to the second drive gear 7 can be engaged and disengaged by theinput side clutch 8. Accordingly, the selection of the combination ofthe operation modes similar to that of the first embodiment is possible.

Third Embodiment

Next, a third embodiment of the present invention will be described,focusing on differences from the first embodiment. Differently from thefirst embodiment, in the vehicular power transmission device accordingto the present embodiment, the input side clutch 8 that engages anddisengages the first motor input shaft 6 and the second engine inputshaft 4 is arranged between the engine 1 and the first drive gear 5 asshown in FIG. 14, not between the first drive gear 5 and the seconddrive gear 7.

In order to realize such the arrangement, a cylindrical engine inputshaft 19 is attached to a portion of the input side clutch 8 thatrotates with the second engine input shaft 4. The cylindrical engineinput shaft 19 coaxially surrounds another portion of the input sideclutch 8 that rotates with the first motor input shaft 6. Thecylindrical engine input shaft 19 coaxially surrounds the first motorinput shaft 6 and extends toward the motor MG1. The cylindrical engineinput shaft 19 rotates with the second engine input shaft 4. The firstdrive gear 5 is fixed not to the second engine input shaft 4 but to anend portion of the cylindrical engine input shaft 19 closer to the motorMG1 between two end portions. The first drive gear 5 rotates with thecylindrical engine input shaft 19.

In the present embodiment, the first motor input shaft 6 is supported bythe cylindrical engine input shaft 19 rotatably, and the cylindricalengine input shaft 19 is supported by the first motor input shaft 6rotatably. Accordingly, the number of bearing members, which areseparately provided for supporting the input shafts 4, 6, 19, can bereduced as compared to the vehicular power transmission device of thefirst embodiment. Since the input side clutch 8 is not arranged betweenthe low gear mechanism and the high gear mechanism, the unit consistingof the low gear mechanism and the high gear mechanism can be madecompact.

In the present embodiment, the engine 1, the engine input shafts 2, 4,the input side clutch 8, the first drive gear 5, the second drive gear7, the first motor input shaft 6 and the motor MG1 are arranged on thesame axis in this order. With such the arrangement, shaft length of theengine input shafts 2, 4 can be shortened, so resistance against thetorsional vibration increases.

The other construction and the operation of the controller 20 of thepresent embodiment are the same as those of the first embodiment.Therefore, like the first embodiment, the second engine input shaft 4that transmits the power from the engine 1 to the first drive gear 5 andthe first motor input shaft 6 that transmits the power from the motorMG1 to the second drive gear 7 can be engaged and disengaged by theinput side clutch 8. Accordingly, the selection of the combination ofthe operation modes similar to that of the first embodiment is possible.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be described,focusing on differences from the first embodiment. The construction ofthe vehicular power transmission device according to the presentembodiment is shown in FIG. 15 (but controller 20 is not shown). Thesame components as the first embodiment are denoted with the samereferential marks as the first embodiment and will not be explained orwill be explained only briefly below.

A major difference of the present embodiment from the first embodimentis that a middle gear mechanism (corresponding to example of secondmotor side gear mechanism) is also provided in addition to the twostages of the low gear mechanism and the high gear mechanism. Areduction gear ratio of the middle gear mechanism is smaller than thatof the low gear mechanism and larger than that of the high gearmechanism.

More specifically, the two stages of the low and middle gear mechanismsare provided on the motor MG1 side of the input side clutch 8 in termsof the power transmission route. Therefore, the engine 1 can use thegear mechanism, which is frequently used by the engine 1 in the hybridvehicle in general, irrespective of the engagement/disengagement of theinput side clutch 8. The motor MG1 can use the first and second motorside gear mechanisms, which are frequently used by the motor MG1 in thehybrid vehicle in general, irrespective of the engagement/disengagementof the input side clutch 8.

More specifically, in the present embodiment, a first motor input shaft6 a that extends from the motor MG1 and that receives the input of thepower generated by the motor MG1 is formed as a cylindrical shaft. Thefirst motor input shaft 6 a extends from the input side clutch 8 towardthe engine 1 and coaxially surrounds the second engine input shaft 4.Therefore, the first motor input shaft 6 is arranged on a side closer tothe engine 1 than the input side clutch 8.

The rotor of the motor MG1 is coaxially fixed to the first motor inputshaft 6 a. Therefore, if the motor MG1 is driven to generate the powerand the rotor of the motor MG1 rotates with respect to a stator of themotor MG1, the first motor input shaft 6 a also rotates with therotation of the rotor.

A second drive gear 7 a and a third drive gear 7 b are pivotally fixedto a portion of the first motor input shaft 6 a on a side closer to theengine 1 than the motor MG1. The second drive gear 7 a and the thirddrive gear 7 b rotate with the rotation of the first motor input shaft 6a.

The second drive gear 7 a meshes with a second driven gear 12 a. Thesecond driven gear 12 a is supported by the output shaft 9 rotatably. Asecond output side clutch 13 a is fixed to the output shaft 9 andengages and disengages the output shaft 9 and the second driven gear 12a.

The third drive gear 7 b meshes with a third driven gear 12 b. The thirddriven gear 12 b is supported by the output shaft 9 rotatably. A thirdoutput side clutch 13 b is fixed to the output shaft 9 and engages anddisengages the output shaft 9 and the third driven gear 12 b.

The first drive gear 5 is provided between the engine 1 and the seconddrive gear 7 a (and third drive gear 7 b). With such the construction,the distance from the engine 1 to the engine side gear mechanism 5, 10,11 can be shortened. As a result, resistance of the engine input shafts2, 4 against the torsional vibration can be maintained high.

In the present embodiment, the motor MG2 may be fixed to the outputshaft 9 as shown by a broken line in FIG. 15 or the motor MG2 may beremoved. In following explanation, it is assumed that the motor MG2 isnot provided.

In the vehicular power transmission device having the above-describedconstruction, the first drive gear 5, the first driven gear 10 and thefirst output side clutch 11 constitute a high gear mechanism like thefirst embodiment.

If the second output side clutch 13 a is engaged, the power transmissionis performed between the output shaft 9 and the second driven gear 12 a.Therefore, the power transmission is performed between the first motorinput shaft 6 a and the output shaft 9 through the second drive gear 7a, the second driven gear 12 a and the second output side clutch 13 a(not through engine input shafts 2, 4). If the second output side clutch13 a is disengaged, the power transmission between the first motor inputshaft 6 a and the output shaft 9 through the second drive gear 7 a, thesecond driven gear 12 a and the second output side clutch 13 a is notperformed. The second drive gear 7 a, the second driven gear 12 a andthe second output side clutch 13 a constitute a low gear mechanism(corresponding to example of first motor side gear mechanism).

If the third output side clutch 13 b is engaged, the power transmissionis performed between the output shaft 9 and the third driven gear 12 b.Therefore, the power transmission is performed between the first motorinput shaft 6 a and the output shaft 9 through the third drive gear 7 b,the third driven gear 12 b and the third output side clutch 13 b. If thethird output side clutch 13 b is disengaged, the power transmissionbetween the first motor input shaft 6 a and the output shaft 9 throughthe third drive gear 7 b, the third driven gear 12 b and the thirdoutput side clutch 13 b is not performed. The third drive gear 7 b, thethird driven gear 12 b and the third output side clutch 13 b constitutea middle gear mechanism (corresponding to example of second motor sidegear mechanism).

The reduction gear ratio of the low gear mechanism is larger than thatof the middle gear mechanism, and the reduction gear ratio of the middlegear mechanism is larger than that of the high gear mechanism.Therefore, in the vehicular power transmission device, the gearmechanism closest to the engine 1 is the high gear mechanism and thegear mechanism closest to the motor MG1 is the low gear mechanism interms of both of the power transmission route and the arrangement.

In such the construction, the controller 20 controls the transmissionroutes and the reduction gear ratios of the powers generated by theengine 1 and the motor MG1 by controlling the driving/non-driving of themotor MG1 and the engagement/disengagement of the input side clutch 8,the first output side clutch 11, the second output side clutch 13 a andthe third output side clutch 13 b based on the various physicalquantities, which are obtained within the vehicle and are similar tothose of the first embodiment.

By such the control of the clutches 8, 11, 13 a, 13 b performed by thecontroller 20, the power generated by the motor MG1 can be transmittedto the driving wheels 16, 17 through any of the low gear mechanism, themiddle gear mechanism and the high gear mechanism. Also, the powergenerated by the engine 1 can be transmitted to the driving wheels 16,17 through any of the low gear mechanism, the middle gear mechanism andthe high gear mechanism.

FIG. 16 shows a correspondence relationship between the control contentsof the clutches 8, 11, 13 a, 13 b by the controller 20 and the gearmechanisms used by the motor MG1 and the engine 1. In FIG. 16, eachcircle mark means engagement of the clutch, and each blank meansdisengagement of the clutch.

For example, an ENG(M)+MG1(M) mode as a combination of an ENG(M) mode,in which the engine 1 transmits the power through the middle gearmechanism, and a MG1(M) mode, in which the motor MG1 transmits the powerthrough the middle gear mechanism, is realized by engaging the inputside clutch 8 and the third output side clutch 13 b and by disengagingthe first output side clutch 11 and the second output side clutch 13 arespectively. In this way, the same gear mechanism can be commonly usedby the engine 1 and the motor MG1.

In addition, for example, an ENG(H)+MG1(M) mode as a combination of anENG(H) mode, in which the engine 1 transmits the power through the highgear mechanism, and the MG1(M) mode, in which the motor MG1 transmitsthe power through the middle gear mechanism, is realized by engaging thefirst output side clutch 11 and the third output side clutch 13 b and bydisengaging the input side clutch 8 and the second output side clutch 13a respectively. In this way, the different gear mechanisms can be usedby the engine 1 and the motor MG1 respectively. However, in this case,because of the structure of the vehicular power transmission device, thegear mechanism used by the engine 1 is limited to the high gearmechanism, and the gear mechanism used by the motor MG1 is limited tothe low gear mechanism or the middle gear mechanism.

In addition, for example, an ENG(H) single mode for using only theENG(H) mode, in which the engine 1 transmits the power through the highgear mechanism, is realized by engaging the first output side clutch 11and by disengaging the input side clutch 8, the second output sideclutch 13 a and the third output side clutch 13 b respectively.

An example of characteristics of the motor MG1 and the engine 1 is shownin FIG. 17 in the same manner as FIG. 8. A solid line 60 in FIG. 17shows necessary driving torque at respective vehicle speeds duringflat-area constant-speed running. Solid lines 61, 62, 63 respectivelyshow upper limits of the driving torque, which can be generated by themotor MG 1 at respective vehicle speeds in the MG1(L) mode, the MG1(M)mode and the MG1(H) mode respectively.

Areas 64, 65, 66 surrounded by broken lines show areas where efficiency(equivalent to gas mileage) is assumed to be equal to or higher than apredetermined reference in the MG1(L) mode, the MG1(M) mode and theMG1(H) mode respectively. Solid lines 67, 68, 69 show ranges (maximumefficiency lines) in which the efficiency is assumed to be the maximumin the ENG(L) mode, the ENG(M) mode and the ENG(H) mode respectively.

Also in the present embodiment, in order to realize the running suitablefor the state of the vehicle, the operation modes of the motor MG1 andthe engine 1 are selected in consideration of the above-describedcharacteristics of the motor MG1 and the engine 1.

The basic concept of the selection of the operation modes of the motorMG1 and the engine 1 is that the most efficient combination is selectedin the relationship between the vehicle speed and the necessary drivingtorque. More specifically, the controller 20 switches the running modebetween the EV main mode and the engine main mode based on the SOC by amethod similar to the method of the first embodiment. The controller 20selects a combination of the operation modes of the motor MG1 and theengine 1 corresponding to the necessary driving torque and the obtainedvehicle speed in each of the EV main mode and the engine main moderespectively by using the corresponding switching map.

In the present embodiment, a switching map shown in FIG. 18 is used asthe switching map for the EV main mode, and a switching map shown inFIG. 19 is used as the switching map for the engine main mode.

Next, concrete contents of partitioning and allotting of the switchingmaps of FIGS. 18 and 19 will be explained. On the switching map for theEV main mode of FIG. 18, a range of the driving torque equal to or lowerthan approximately 400 Nm defines a single block 71 across the entirevehicle speed range. A combination of the MG1(M) mode and thenon-driving mode of the engine 1 is allotted to the block 71. It isbecause the area 65 of the high efficiency in the MG1(M) mode exists inthe center of the block 71. This combination is realized by disengagingthe input side clutch 8, the first output side clutch 11 and the secondoutput side clutch 13 a and by engaging the third output side clutch 13b respectively.

A block 72 covering a driving torque range immediately above the block71 is defined in a range from start to low-speed or middle-speedacceleration ranging from 0 km/h to approximately 70 km/h. A combinationof the MG1(L) mode and the non-driving mode of the engine 1 is allottedto the block 72. It is because the area 64 of the high efficiency in theMG1(L) mode exists in the center of the block 72. This combination isrealized by disengaging the input side clutch 8, the first output sideclutch 11 and the third output side clutch 13 b and by engaging thesecond output side clutch 13 a respectively.

A block 73 covering a driving torque range immediately above the block72 is defined in a range from start to low-speed or middle-speedacceleration ranging from 0 km/h to approximately 70 km/h. A combinationof the MG1(L) mode and the ENG(L) mode is allotted to the block 73. Byusing the motor MG1 and the engine 1 together in this way, while thepower generated by the motor MG1 is the driving torque in or near thehigh efficiency area 64 of the MG1(L) mode of FIG. 17 and while thepower generated by the engine 1 is the driving torque in or near thehigh efficiency range 67 of the ENG(L) mode of FIG. 17, the drivingtorque of the axle 15 larger than the high efficiency area 64 or range67 can be realized. This combination is realized by disengaging thefirst output side clutch 11 and the third output side clutch 13 b and byengaging the input side clutch 8 and the second output side clutch 13 arespectively.

A block 74 covering a driving torque range immediately above the block71 is defined in a high-speed range over 70 km/h. A combination of theMG1(M) mode and the ENG(H) mode is allotted to the block 74. By usingthe motor MG1 and the engine 1 together in this way, while the powergenerated by the motor MG1 is the driving torque in or near the highefficiency area 65 of the MG1(M) mode of FIG. 17 and while the powergenerated by the engine 1 is the driving torque in or near the highefficiency range 69 of the ENG(H) mode of FIG. 17, the driving torque ofthe axle 15 larger than the high efficiency area 65 or range 69 can berealized. This combination is realized by disengaging the input sideclutch 8 and the second output side clutch 13 a and by engaging thefirst output side clutch 11 and the third output side clutch 13 brespectively.

A block 75 covering a driving torque range immediately above the block74 is defined in a high-speed range over 60 km/h. A combination of theMG1(M) mode and the ENG(M) is allotted to the block 75. By using themotor MG1 and the engine 1 together in this way, while the powergenerated by the motor MG1 is the driving torque in or near the highefficiency area 65 of the MG1(M) mode of FIG. 17 and while the powergenerated by the engine 1 is the driving torque in or near the highefficiency range 68 of the ENG(M) mode of FIG. 17, the driving torque ofthe axle 15 larger than the high efficiency area 65 or range 68 can berealized. Higher driving torque can be realized since the value of thedriving torque is higher in the high efficiency range 68 of the ENG(M)mode than in the high efficiency range 69 of the ENG(H) mode. Thiscombination is realized by disengaging the first output side clutch 11and the second output side clutch 13 a and by engaging the input sideclutch 8 and the third output side clutch 13 b respectively.

In the EV main mode, the input side clutch 8 is engaged only in theblocks 73, 75, in which the engine 1 and the motor MG1 use the same gearmechanism. Therefore, the input side clutch 8 does not operate unlessthe necessary driving torque becomes very large. Therefore, wear of theinput side clutch 8 and the friction plates of the input side clutch 8can be reduced significantly. At the same time, the driving energy ofthe actuator can be reduced significantly.

On the switching map for the engine main mode of FIG. 19, in a range ofvery low vehicle speed ranging from 0 km/h to 20 km/h, a MG1(M) singlemode for driving the vehicle only in the MG1(M) mode is allotted to ablock 81 where the necessary driving torque is equal to or lower thanapproximately 400 Nm. In this way, also in the engine main mode mainlyusing the engine 1, the vehicle is driven only with the motor MG1 in thevery low speed range where the electric power consumption is not verylarge. This combination is realized by disengaging the input side clutch8, the first output side clutch 11 and the second output side clutch 13a and by engaging the third output side clutch 13 b respectively.

A block 82 covering a driving torque range immediately above the block81 is defined in the very low speed range. A MG1(L) single mode fordriving the vehicle only in the MG1(L) mode is allotted to the block 82.In this way, also in the engine main mode mainly using the engine 1, thevehicle is driven only with the motor MG1 in the very low speed rangewhere the electric power consumption is not very large. The drivingtorque is larger than in the block 81. Therefore, instead of the MG1(M)mode, the MG1(L) mode having the high efficiency area 64 in the highdriving torque range is used. This combination is realized bydisengaging the input side clutch 8, the first output side clutch 11 andthe third output side clutch 13 b and by engaging the second output sideclutch 13 a respectively.

A combination of the MG1(M) mode and the ENG(H) mode is allotted to ablock 83 having the high efficiency area 65 of the MG1(M) mode in itscenter. A combination of the MG1(H) mode and the ENG(H) mode is allottedto a block 84 having the high efficiency area 66 of the MG1(H) mode inits center. This combination allotted to the block 84 is realized bydisengaging the second output side clutch 13 a and the third output sideclutch 13 b and by engaging the input side clutch 8 and the first outputside clutch 11 respectively.

A block 85 covering a driving torque range immediately above the blocks83, 84 is defined in a middle to high speed range ranging fromapproximately 20 km/h to approximately 150 km/h. A combination of theMG1(M) mode and the ENG(M) is allotted to the block 85. By using themotor MG1 and the engine 1 together in this way, while the powergenerated by the motor MG1 is the driving torque in or near the highefficiency area 65 of the MG1(M) mode of FIG. 17 and while the powergenerated by the engine 1 is the driving torque in or near the highefficiency range 68 of the ENG(M) mode of FIG. 17, the driving torque ofthe axle 15 larger than the high efficiency area 65 or range 68 can berealized.

A block 86 covering a driving torque range immediately above the blocks82, 85 is defined in a middle speed range ranging from approximately 20km/h to approximately 60 km/h. A combination of the MG1(L) mode and theENG(L) mode is allotted to the block 86. By using the motor MG1 and theengine 1 together in this way, while the power generated by the motorMG1 is the driving torque in or near the high efficiency area 64 of theMG1(L) mode of FIG. 17 and while the power generated by the engine 1 isthe driving torque in or near the high efficiency range 67 of the ENG(L)mode of FIG. 17, the driving torque of the axle 15 larger than the highefficiency area 64 or range 67 can be realized.

In the engine main mode, the input side clutch 8 is engaged only in theblocks 84, 85, 86, in which the engine 1 and the motor MG1 use the samegear mechanism. Therefore, the input side clutch 8 does not operateunless the necessary driving torque becomes very large or the vehiclespeed becomes very high. Therefore, wear of the input side clutch 8 andthe friction plates of the input side clutch 8 can be reducedsignificantly. At the same time, the driving energy of the actuator canbe reduced significantly.

As explained above, the controller 20 selectively uses the EV main modefor mainly using the motor MG1 or the engine main mode for mainly usingthe engine 1 according to the SOC of the vehicle driving battery. Thecontroller 20 selects the efficient combination of thedriving/non-driving and the reduction gear ratios of the motor MG1 andthe engine 1 in each of the EV main mode and the engine main moderespectively according to the necessary driving torque and the vehiclespeed. In order to realize the selected combination, the controller 20controls the engagement/disengagement of the input side clutch 8, thefirst output side clutch 11, the second output side clutch 13 a and thethird output side clutch 13 b and the driving/non-driving of the motorMG1.

As shown in the switching maps of FIGS. 18 and 19, in the area (definedby vehicle speed from 0 to 60 km/h and driving torque from 0 to 300 Nm)realized in the normal running, the ENG (H) mode is used more often thanthe ENG (L) mode and the MG1(M) mode and the MG1(L) mode are used moreoften than the MG1(H) mode.

In this way, also when the multi-stages of gear mechanisms of three ormore stages are used, effects similar to the first embodiment can beobtained.

Fifth Embodiment

Next, a fifth embodiment of the present invention will be described,focusing on differences from the first embodiment. The construction ofthe vehicular power transmission device according to the presentembodiment is shown in FIG. 20 (but controller 20 is not shown). Thesame components as the first embodiment are denoted with the samereferential marks as the first embodiment and will not be explained orwill be explained only briefly below.

A major difference of the present embodiment from the first embodimentis that a middle gear mechanism is also provided in addition to the twostages of the low gear mechanism and the high gear mechanism like thefourth embodiment. The two stages of the low gear mechanism and themiddle gear mechanism are provided on the motor MG1 side of the inputside clutch 8 in terms of both of the power transmission route and thearrangement.

More specifically, a second drive gear 7 c and a third drive gear 7 dare pivotally fixed to the first motor input shaft 6 such that thesecond drive gear 7 c and the third drive gear 7 d rotate with therotation of the first motor input shaft 6.

The second drive gear 7 c meshes with a second driven gear 12 c, whichis supported by the output shaft 9 rotatably. A second output sideclutch 13 c is fixed to the output shaft 9 and engages and disengagesthe output shaft 9 and the second driven gear 12 c.

A third drive gear 7 d meshes with a third driven gear 12 d, which issupported by the output shaft 9 rotatably. A third output side clutch 13d is fixed to the output shaft 9 and engages and disengages the outputshaft 9 and the third driven gear 12 d. The motor MG2 is not provided inthe present embodiment.

The operation of the controller 20 in the vehicular power transmissiondevice having the above-described construction is the same as the fourthembodiment.

In this way, also when the multi-stages of gear mechanisms of three ormore stages are used, effects similar to the first embodiment can beobtained.

Sixth Embodiment

Next, a sixth embodiment of the present invention will be described,focusing on differences from the first embodiment. As shown in FIG. 21,in the vehicular power transmission device according to the presentembodiment, the motor MG1 and the second drive gear 7 (constituting lowgear mechanism) are arranged between the first drive gear 5(constituting high gear mechanism) and the engine 1 differently from thefirst embodiment.

More specifically, the input side clutch 8 is attached between thedamper 3 and the first drive gear 5 on the second engine input shaft 4.The first motor input shaft 6, which is formed in a cylindrical shapedifferently from the first embodiment, is fixed to the input side clutch8. A function of the input side clutch 8 to engage and disengage thesecond engine input shaft 4 and the first motor input shaft 6 is thesame as the first embodiment.

The first motor input shaft 6 coaxially surrounds the second engineinput shaft 4 and extends from the input side clutch 8 toward the firstdrive gear 5. The motor MG1 and the second drive gear 7 are fixed to thefirst motor input shaft 6 in this order from a side closer to the inputside clutch 8. Therefore, the input side clutch 8 is arranged betweenthe motor MG1 and the engine 1.

Also the second driven gear 12 and the second output side clutch 13 arearranged on the differential gear 14 side of the first driven gear 10and the first output side clutch 11 in conformity with the arrangementof the second drive gear 7. Therefore, differently from the firstembodiment, the high gear mechanism 5, 10, 11 is arranged on a fartherside of the low gear mechanism 7, 12, 13 from the engine 1.

In this way, the motor MG1 is positioned closer to the engine 1 than thefirst drive gear 5 (high gear mechanism) and the second drive gear 7(low gear mechanism) are. Therefore, the motor MG1 can be arranged in aplace where a clutch, a torque converter and the like have been placedin a conventional vehicle. Thus, the space can be used effectively. Byextending the distance between the motors MG1, MG2, a degree of freedomof an installation dimension of the motor MG2 can be increased whileavoiding interference with the motor MG1.

The other construction and the operation of the controller 20 of thepresent embodiment are the same as those of the first embodiment.Accordingly, selection of the combination of the operation modes similarto that of the first embodiment is possible. The same component isdenoted with the same sign between FIG. 1 and FIG. 21.

Seventh Embodiment

Next, a seventh embodiment of the present invention will be described,focusing on differences from the first embodiment. As shown in FIG. 22,in the vehicular power transmission device according to the presentembodiment, the motor MG1 and the second drive gear 7 (constituting lowgear mechanism) are arranged between the first drive gear 5(constituting high gear mechanism) and the engine 1 differently from thefirst embodiment.

More specifically, the input side clutch 8 is attached between thedamper 3 and the first drive gear 5 on the second engine input shaft 4.The first motor input shaft 6, which is formed in a cylindrical shapedifferently from the first embodiment, is fixed to the input side clutch8. A function of the input side clutch 8 to engage and disengage thesecond engine input shaft 4 and the first motor input shaft 6 is thesame as the first embodiment.

The first motor input shaft 6 coaxially surrounds the second engineinput shaft 4 and extends from the input side clutch 8 toward the engine1. The second drive gear 7 and the motor MG1 are fixed to the firstmotor input shaft 6 in this order from a side closer to the input sideclutch 8. Therefore, the input side clutch 8 is arranged between thefirst drive gear 5 (high gear mechanism) and the second drive gear 7(low gear mechanism).

Also the second driven gear 12 and the second output side clutch 13 arearranged on the differential gear 14 side of the first driven gear 10and the first output side clutch 11 in conformity with the arrangementof the second drive gear 7. Therefore, the high gear mechanism 5, 10, 11is arranged on a farther side of the low gear mechanism 7, 12, 13 fromthe engine 1 differently from the first embodiment.

In this way, the motor MG1 is arranged closer to the engine 1 than thefirst drive gear 5 (high gear mechanism) and the second drive gear 7(low gear mechanism) are. Therefore, the motor MG1 can be arranged in aplace where a clutch, a torque converter and the like have been placedin a conventional vehicle. Thus, the space can be used effectively. Byextending the distance between the motors MG1, MG2, a degree of freedomof an installation dimension of the motor MG2 can be increased whileavoiding interference with the motor MG1.

The other construction and the operation of the controller 20 of thepresent embodiment are the same as those of the first embodiment.Accordingly, selection of the combination of the operation modes similarto that of the first embodiment is possible. The same component isdenoted with the same sign between FIG. 1 and FIG. 22.

Eighth Embodiment

Next, an eighth embodiment of the present invention will be described,focusing on differences from the first embodiment. The construction ofthe vehicular power transmission device according to the presentembodiment is shown in FIG. 23 (but controller 20 is not shown). Thesame components as the first embodiment are denoted with the samereferential marks as the first embodiment and will not be explained orwill be explained only briefly below.

Differences of the present embodiment from the first embodiment areconstructions of a high gear mechanism (corresponding to example ofengine side gear mechanism), a low gear mechanism (corresponding toexample of first motor side gear mechanism) and an output shaft.

First, the high gear mechanism will be explained concretely. The highgear mechanism of the first embodiment (refer to FIG. 1) consists of thefirst drive gear 5, the first driven gear 10, and the first output sideclutch 11. The high gear mechanism of the present embodiment consists ofan engine side planetary gear mechanism Pe and a clutch 21.

In the engine side planetary gear mechanism Pe, a sun gear Se isconnected to the first engine input shaft 2, and a ring gear Re is fixed(to body of vehicle, for example). The clutch 21 engages and disengagesa carrier Ce of the engine side planetary gear mechanism Pe and an end(engine 1 side end) of a first output shaft 9 a in accordance withcontrol by the controller 20.

With such the construction, the power transmitted to the first engineinput shaft 2 (from engine 1 or input side clutch 8) is transmitted fromthe sun gear Se to the carrier Ce at a reduction gear ratiocorresponding to the construction of the engine side planetary gearmechanism Pe. If the clutch 21 is engaged at that time, the power isfurther transmitted from the carrier Ce to the first output shaft 9 a.

Next, the low gear mechanism will be explained concretely. The low gearmechanism of the first embodiment (refer to FIG. 1) consists of thesecond drive gear 7, the second driven gear 12, and the second outputside clutch 13. The low gear mechanism of the present embodimentconsists of a motor side planetary gear mechanism Pm and a clutch 23.

In the motor side planetary gear mechanism Pm, a sun gear Sm isconnected to the first motor input shaft 6, and a ring gear Rm is fixed(to body of vehicle, for example). The clutch 23 engages and disengagesa carrier Cm of the motor side planetary gear mechanism Pm and the otherend (motor MG1 side end) of the first output shaft 9 a in accordancewith the control by the controller 20.

With such the construction, the power transmitted to the first motorinput shaft 6 (from motor MG1 or input side clutch 8) is transmittedfrom the sun gear Sm to the carrier Cm at a reduction gear ratiocorresponding to the construction of the motor side planetary gearmechanism Pm, which is larger than the reduction gear ratiocorresponding to the construction of the engine side planetary gearmechanism Pe. If the clutch 23 is engaged at that time, the power isfurther transmitted from the carrier Cm to the first output shaft 9 a.

In the present embodiment, both of the reduction gear ratios of the highgear mechanism and the low gear mechanism are larger than 1. Thereduction gear ratio of the low gear mechanism is larger than thereduction gear ratio of the high gear mechanism.

Next, the output shaft will be explained concretely. In the presentembodiment, the first output shaft 9 a, a gear 9 b, a gear 9 c and asecond output shaft 9 d are provided in place of the output shaft 9 ofthe first embodiment (refer to FIG. 1).

The first output shaft 9 a is a cylindrical power transmission shaftsurrounding the first engine input shaft 2, the first motor input shaft6 and the input side clutch 8. The first output shaft 9 a is arrangedcoaxially with the first engine input shaft 2 and the first motor inputshaft 6.

The power generated by the motor MG2 is inputted to the second outputshaft 9 d extending from the motor MG2. The second output shaft 9 d isarranged to be parallel and lateral to the first engine input shaft 2,the first motor input shaft 6 and the first output shaft 9 a. The secondoutput shaft 9 d outputs the power to be transmitted to the differentialgear 14, the axle 15 and the like.

The gear 9 b is fixed to the first output shaft 9 a and rotates with thefirst output shaft 9 a. The gear 9 c is fixed to the second output shaft9 d and rotates with the second output shaft 9 d. The gears 9 b, 9 cmesh with each other and rotate together at a rotation number ratiocorresponding to a ratio between their teeth.

Also by using such the construction, when the input side clutch 8 isengaged, the power can be transmitted between the high gear mechanismPe, 11 on the first engine input shaft 2 and the low gear mechanism Pm,13 on the first motor input shaft 6 like the first embodiment. When theinput side clutch 8 is disengaged, the power of the first engine inputshaft 2 and the power of the first motor input shaft 6 can betransmitted to the first output shaft 9 a, the gear 9 b, the gear 9 cand the second output shaft 9 d at the different reduction gear ratiosat the same time.

The operation of the controller 20 of the present embodiment is the sameas the first embodiment. However, the same control as theengagement/disengagement control of the first output side clutch 11 isapplied to the clutch 21 in place of the first output side clutch 11.The same control as the engagement/disengagement control of the secondoutput side clutch 13 is applied to the clutch 23 in place of the secondoutput side clutch 13.

Ninth Embodiment

Next, a ninth embodiment of the present invention will be described,focusing on differences from the eighth embodiment. The construction ofthe vehicular power transmission device according to the presentembodiment is shown in FIG. 24 (but controller 20 is not shown). Thesame components as the first embodiment are denoted with the samereferential marks as the first embodiment and will not be explained orwill be explained only briefly below.

The operation of the controller 20 of the present embodiment is the sameas the eighth embodiment. A difference of the construction of thevehicular power transmission device of the present embodiment from thefirst embodiment is a construction of a high gear mechanism (engine sideplanetary gear mechanism Pe and clutch 21).

More specifically, in the engine side planetary gear mechanism Pe, acarrier Ce is connected to the first engine input shaft 2, and a ringgear Re is fixed (to body of vehicle, for example). The clutch 21engages and disengages a sun gear Se of the engine side planetary gearmechanism Pe and an end (engine 1 side end) of the first output shaft 9a in accordance with the control by the controller 20.

With such the construction, the power transmitted to the first engineinput shaft 2 (from engine 1 or input side clutch 8) is transmitted fromthe carrier Ce to the sun gear Se at a reduction gear ratiocorresponding to the construction of the engine side planetary gearmechanism Pe. If the clutch 21 is engaged at that time, the power isfurther transmitted from the sun gear Se to the first output shaft 9 a.

Also when such the construction is used, an effect similar to the eighthembodiment can be obtained. According to the present embodiment, theconnection relationship between the sun gear Se and the carrier Ce isreversed from the eighth embodiment. Thus, an overdrive at the reductiongear ratio of the high gear mechanism smaller than 1 can be realized.

Tenth Embodiment

Next, a tenth embodiment of the present invention will be described,focusing on differences from the eighth embodiment. The construction ofthe vehicular power transmission device according to the presentembodiment is shown in FIG. 25 (but controller 20 is not shown). Thesame components as the first embodiment are denoted with the samereferential marks as the first embodiment and will not be explained orwill be explained only briefly below.

The operation of the controller 20 of the present embodiment is the sameas the eighth embodiment. Major differences of the construction of thevehicular power transmission device of the present embodiment from thefirst embodiment are constructions of a high gear mechanism (engine sideplanetary gear mechanism Pe and clutch 21) and a low gear mechanism(motor side planetary gear mechanism Pm and clutch 23).

First, the high gear mechanism will be explained concretely. In theengine side planetary gear mechanism Pe, a sun gear Se is connected tothe first engine input shaft 2, and a carrier Ce is fixed (to body ofvehicle, for example). The clutch 21 engages and disengages the ringgear Re of the engine side planetary gear mechanism Pe and an end(engine 1 side end) of the first output shaft 9 a in accordance with thecontrol by the controller 20.

With such the construction, the power transmitted to the first engineinput shaft 2 (from engine 1 or input side clutch 8) is transmitted fromthe sun gear Se to the ring gear Re at a reduction gear ratiocorresponding to the construction of the engine side planetary gearmechanism Pe. If the clutch 21 is engaged at that time, the power isfurther transmitted from the ring gear Re to the first output shaft 9 a.

Next, the low gear mechanism will be explained concretely. In the motorside planetary gear mechanism Pm, a sun gear Sm is connected to thefirst motor input shaft 6, and a carrier Cm is fixed (to body ofvehicle, for example). The clutch 23 engages and disengages the ringgear Rm of the motor side planetary gear mechanism Pm and the other end(motor MG1 side end) of the first output shaft 9 a in accordance withthe control by the controller 20.

With such the construction, the power transmitted to the first motorinput shaft 6 (from motor MG1 or input side clutch 8) is transmittedfrom the sun gear Sm to the ring gear Rm at a reduction gear ratiocorresponding to the construction of the motor side planetary gearmechanism Pm, which is larger than the reduction gear ratiocorresponding to the construction of the engine side planetary gearmechanism Pe. If the clutch 23 is engaged at that time, the power isfurther transmitted from the ring gear Rm to the first output shaft 9 a.

Also by using such the construction, when the input side clutch 8 isengaged, the power can be transmitted between the high gear mechanismPe, 11 on the first engine input shaft 2 and the low gear mechanism Pm,13 on the first motor input shaft 6 like the eighth embodiment. When theinput side clutch 8 is disengaged, the power of the first engine inputshaft 2 and the power of the first motor input shaft 6 can betransmitted to the first output shaft 9 a, the gear 9 b, the gear 9 cand the second output shaft 9 d at the different reduction gear ratiosat the same time.

Eleventh Embodiment

Next, an eleventh embodiment of the present invention will be described.A difference of the present embodiment from the first embodiment is onlythat a switching map shown in FIG. 26 is used as a switching map of theengine main mode in place of the switching map shown in FIG. 10. Theswitching map of FIG. 26 is different from the switching map of FIG. 10in that the blocks 51, 52 of FIG. 10 are partly replaced with a block 55for performing an electric power generation mode. The replaced part inthe block 51 of FIG. 10 is the area 55 of the lowest speed (range ofvehicle speed from 0 km/h to approximately 30 km/h in presentembodiment) and the lowest load (range of driving torque from 0 Nm toapproximately 200 Nm in present embodiment).

Thus, in the area of the low speed and the low load, the electric poweris generated in the motor MG1 by using the power generated in the engine1. Thus, the vehicle driving battery can be charged not through the gearmechanisms (5, 7, 7 a, 7 c, 10, 11, 12, 12 a, 12 c, 13, 13 a, 13 c), soefficiency improves and the fall of the SOC can be suppressed.

Twelfth Embodiment

Next, a twelfth embodiment of the present invention will be described. Adifference of the present embodiment from the eleventh embodiment isonly that a switching map shown in FIG. 27 is used as a switching map ofthe engine main mode in place of the switching map shown in FIG. 26. Adifference of the switching map of FIG. 27 from the switching map ofFIG. 26 is that the block 54, to which the combination of the MG1(H)mode, the driving mode of the motor MG2 and the ENG(H) mode is allotted,is expanded to the entire block 52 and a part of the block 53 where thetorque is low in FIG. 10 and changed into a block 56.

A dotted arrow mark 91 in FIG. 27 represents running that makes thetransition from low-speed low-load running to low-speed middle-loadrunning and that occurs often during the running in an urban area. Withthe above-described construction, when the running shown by the dottedline 91 occurs, after the running enters the block 52 from the block 55,the time number of shifting of gears can be reduced by performing therunning mainly in the ENG(H) mode as explained above. Actually, when theswitching map shown in FIG. 26 is used, the shifting of gears occurs ina state shown by x mark 92. In contrast, the shifting of gears does notoccur in the present embodiment.

A dotted arrow mark 93 in FIG. 27 represents acceleration for over-take(i.e., transition from middle-speed low-load running to middle-speedmiddle-load running). When such the running shown by the dotted arrowmark 93 occurs, the time number of the shifting of gears can be reducedby performing the running mainly in the ENG(H) mode as already explainedabove. Actually, when the switching map shown in FIG. 26 is used, theshifting of gears occurs in a state of x mark 94. In contrast, theshifting of gears does not occur in the present embodiment. Furthermore,when a transition is made from the block 51 to the block 56, only themotor MG1 is operated, so the shifting of gears does not occur.

In this way, in the present embodiment, the time number of shifting ofgears can be reduced by using the switching map of FIG. 27, so ridingcomfort can be improved.

Other Embodiments

The scope of the present invention is not limited to the above-explainedembodiments. Rather, the scope of the present invention includes variousforms capable of realizing the functions of components that specify thepresent invention.

(1) For example, the engagement/disengagement of the input side clutch 8is controlled by the actuator in the above-described embodiments. Whenthe input side clutch 8 is engaged, the driving torque is transmittedfrom the second engine input shaft 4 to the first motor input shaft 6(or first motor input shaft 6 a) and the driving torque is transmittedfrom the first motor input shaft 6 (or first motor input shaft 6 a) tothe second engine input shaft 4. That is, bidirectional transmission ofthe driving torque is enabled when the input side clutch 8 is engaged.

However, the present invention is not limited thereto. For example, inplace of the input side clutch 8 of each embodiment having theabove-described construction, a widely known one-way clutch or two-wayclutch may be adopted. The one-way clutch or the two-way clutch is fixedsuch that the driving torque is transmitted only from the second engineinput shaft 4 side to the first motor input shaft 6 side (or first motorinput shaft 6 a side).

By adopting such the one-way clutch or two-way clutch, it becomesunnecessary to control the engagement/disengagement of the input sideclutch 8 by using the actuator. As a result, it becomes unnecessary toprovide the actuator. It is because the gear mechanism (low gearmechanism or middle gear mechanism) provided on the first motor inputshaft 6 side (or first motor input shaft 6 a side) has the largerreduction gear ratio than the high gear mechanism provided on the secondengine input shaft 4 side.

That is, for example, when the MG1(M)+ENG(H) mode is selected in thefifth embodiment, the rotation speed of the first motor input shaft 6 ishigher than the rotation speed of the second engine input shaft 4.Therefore, the one-way clutch idles and provides the same situation asthe situation where the input side clutch 8 is disengaged. As a result,the MG1(M)+ENG (H) mode is realized. That is, the different reductiongear ratios can be selected between the motor MG1 and the engine 1.

When the MG1(L)+ENG(L) mode is selected, the driving torque istransmitted from the second engine input shaft 4 to the first motorinput shaft 6. Therefore, the MG1(L)+ENG(L) mode is realized. Since thedriving torque is not transmitted from the first motor input shaft 6 tothe second engine input shaft 4, it becomes impossible to realize theoperation mode of the MG1(H) mode and the operation mode combining theMG1(H) mode. However, the efficient running can be performed evenwithout selecting the operation mode of the MG1(H) mode or the operationmode combining the MG1(H) mode as in the EV main mode of the fifthembodiment.

In this way, by adopting the one-way clutch or the two-way clutch as theinput side clutch 8, it becomes impossible to realize the MG1(H) modeand the operation mode combining the MG1(H) mode. However, the actuatorfor the input side clutch 8 can be abolished without deteriorating thegas mileage largely, so the construction and the control of thevehicular power transmission device can be simplified correspondingly.

(2) In each of the above-described embodiments, the damper 3 is providedbetween the engine 1 and the first drive gear 5. Alternatively, thedamper may be abolished, and the first engine input shaft 2 and thesecond engine input shaft 4 may be integrated.

(3) In each of the above-described embodiments, a clutch may be providedto the second engine input shaft 4 between the damper 3 and the firstdrive gear 5.

(4) In the above-described fourth embodiment, the second output sideclutch 13 a and the third output side clutch 13 b may be formed integralwith each other. In the above-described fifth embodiment, the secondoutput side clutch 13 c and the third output side clutch 13 d may beformed integral with each other.

(5) The clutches 11, 13, 13 a-13 d may be attached to the input shaft 4,6, 6 a, 18, 19 side instead of the output shaft 9 side. In this case,the drive gears 5, 7, 7 a-7 d may be attached to the input shaftrotatably, the driven gears 10, 12, 12 a-12 d may be attached to theoutput shaft 9 pivotally, and the clutches 11, 13, 13 a-13 d may bestructured to engage and disengage the input shafts 4, 6, 6 a, 18, 19and the drive gears 5, 7, 7 a-7 d.

(6) Each of the functions realized by the controller 20 through theexecution of the program in each of the above-described embodiments maybe realized by using a hardware having such the function (for example,FPGA enabling programming of circuit configuration).

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A vehicular power transmission device thattransmits powers generated by an engine, a first motor, and a secondmotor to an axle of a vehicle, the power transmission device comprising:an engine input shaft, to which the power generated by the engine isinputted and which transmits the inputted power of the engine; a motorinput shaft, to which the power generated by the first motor is inputtedand which transmits the inputted power of the first motor; an outputshaft, to which the power generated by the second motor is inputted, foroutputting the power to be transmitted to the axle; an engine side gearmechanism provided to the engine input shaft for transmitting the powerof the engine input shaft to the output shaft not through the motorinput shaft; a first motor side gear mechanism provided to the motorinput shaft for transmitting the power of the motor input shaft to theoutput shaft not through the engine input shaft; and an input sideclutch for engaging and disengaging the engine input shaft and the motorinput shaft, wherein the engine input shaft and the first motor inputshaft are arranged to be parallel and coaxial to each other, the firstmotor side gear mechanism includes a motor side output side clutch forperforming and nonperforming transmission of the power from the motorinput shaft to the output shaft, and the motor side output side clutchis fixed to the output shaft.
 2. The vehicular power transmission deviceas in claim 1, wherein the first motor side gear mechanism includes amotor side driven gear to which the power of the motor input shaft istransmitted, the motor side driven gear is supported by the outputshaft, and the power generated by the second motor is transmitted to theoutput shaft not through the motor side output side clutch and the motorside driven gear.
 3. The vehicular power transmission device as in claim1, wherein the first motor side gear mechanism includes a motor sidedriven gear to which the power of the motor input shaft is transmitted,the motor side driven gear is supported by the output shaft, the outputshaft includes an axle side portion and a motor side portion, the axleside portion of the output shaft is located closer to the axle than themotor side driven gear, the motor side portion of the output shaft islocated closer to the second motor than the motor side driven gear, andthe motor side output side clutch engages and disengages the motor sidedriven gear and the axle side portion of the output shaft.
 4. Thevehicular power transmission device as in claim 1, wherein the engineside gear mechanism includes an engine side output side clutch forperforming and nonperforming transmission of the power from the engineinput shaft to the output shaft, and the engine side output side clutchis fixed to the output shaft.
 5. The vehicular power transmission deviceas in claim 4, wherein the engine side gear mechanism includes an engineside driven gear to which the power of the engine input shaft istransmitted, the engine side driven gear is supported by the outputshaft, and the power generated by the second motor is transmitted to theoutput shaft not through the engine side output side clutch and theengine side driven gear.
 6. The vehicular power transmission device asin claim 4, wherein the engine side gear mechanism includes an engineside driven gear to which the power of the engine input shaft istransmitted, the engine side driven gear is supported by the outputshaft, the first motor side gear mechanism includes a motor side drivengear to which the power of the motor input shaft is transmitted, themotor side driven gear is supported by the output shaft, the outputshaft includes an axle side portion and a motor side portion, the axleside portion of the output shaft is located closer to the axle than themotor side driven gear, the motor side portion of the output shaft islocated closer to the second motor than the motor side driven gear, andthe engine side output side clutch engages and disengages the engineside driven gear and the axle side portion of the output shaft.
 7. Thevehicular power transmission device as in claim 1, wherein when theinput side clutch is engaged, the power transmission is enabled betweenthe engine side gear mechanism on the engine input shaft and the firstmotor side gear mechanism on the motor input shaft.
 8. The vehicularpower transmission device as in claim 1, wherein when the input sideclutch is disengaged, the power of the engine input shaft and the powerof the motor input shaft are enabled to be transmitted to the outputshaft at different reduction gear ratios at the same time.
 9. Thevehicular power transmission device as in claim 1, wherein a reductiongear ratio of the engine side gear mechanism is smaller than a reductiongear ratio of the first motor side gear mechanism.
 10. The vehicularpower transmission device as in claim 1, wherein a reduction gear ratioof the engine side gear mechanism is the smallest among reduction gearratios of gear mechanisms provided to the vehicular power transmissiondevice, and a reduction gear ratio of the first motor side gearmechanism is the largest among the reduction gear ratios of the gearmechanisms provided to the vehicular power transmission device.
 11. Thevehicular power transmission device as in claim 1, further comprising: asecond motor side gear mechanism provided to the motor input shaft fortransmitting the power of the motor input shaft to the output shaft notthrough the engine input shaft, wherein a reduction gear ratio of thefirst motor side gear mechanism and a reduction gear ratio of the secondmotor side gear mechanism are larger than a reduction gear ratio of theengine side gear mechanism.
 12. The vehicular power transmission deviceas in claim 1, wherein the engine side gear mechanism is arrangedbetween the first motor side gear mechanism and the engine.
 13. Thevehicular power transmission device as in claim 12, wherein the inputside clutch is arranged between the engine side gear mechanism and thefirst motor side gear mechanism.
 14. The vehicular power transmissiondevice as in claim 12, wherein the input side clutch is arranged betweenthe first motor and the first motor side gear mechanism, the motor inputshaft includes a cylindrical motor input shaft fixed to a portion of theinput side clutch that rotates with the motor input shaft, thecylindrical motor input shaft surrounds another portion of the inputside clutch that rotates with the engine input shaft and extends towardthe engine to surround the engine input shaft, the cylindrical motorinput shaft is structured to rotate with the other part of the motorinput shaft, and the first motor side gear mechanism is fixed to an endportion of the cylindrical motor input shaft closer to the enginebetween two end portions of the cylindrical motor input shaft.
 15. Thevehicular power transmission device as in claim 12, wherein the inputside clutch is arranged between the engine and the engine side gearmechanism, the engine input shaft includes a cylindrical engine inputshaft fixed to a portion of the input side clutch that rotates with theengine input shaft, the cylindrical engine input shaft surrounds anotherportion of the input side clutch that rotates with the motor input shaftand extends toward the motor to surround the motor input shaft, thecylindrical engine input shaft is structured to rotate with the otherpart of the engine input shaft, and the engine side gear mechanism isfixed to an end portion of the cylindrical engine input shaft closer tothe first motor between two end portions of the cylindrical engine inputshaft.
 16. The vehicular power transmission device as in claim 1,wherein the first motor is arranged between the engine and the firstmotor side gear mechanism, and the engine side gear mechanism isarranged on a farther side of the first motor side gear mechanism fromthe engine.
 17. The vehicular power transmission device as in claim 16,wherein the input side clutch is arranged between the first motor andthe engine.
 18. The vehicular power transmission device as in claim 16,wherein the input side clutch is arranged between the engine side gearmechanism and the first motor side gear mechanism.
 19. The vehicularpower transmission device as in claim 1, wherein the input side clutchis a clutch that transmits driving torque only from the engine inputshaft side to the motor input shaft side, and a reduction gear ratio ofthe motor side gear mechanism is larger than a reduction gear ratio ofthe engine side gear mechanism.
 20. The vehicular power transmissiondevice as in claim 1, further comprising: a controller for controllingtransmission routes and reduction gear ratios of the powers generated bythe engine and the first motor by controlling theengagement/disengagement of the input side clutch, the motor side gearmechanism and the engine side gear mechanism based on a physicalquantity obtained within the vehicle, wherein the controller selectsoperation modes of the engine and the first motor allotted to theobtained physical quantity based on a predetermined switching map thatallots the operation modes to a value of the physical quantity andrealizes the selected operation modes by controlling theengagement/disengagement of the input side clutch, the motor side gearmechanism and the engine side gear mechanism.
 21. The vehicular powertransmission device as in claim 20, wherein the first motor rotatesusing an electric power of a battery mounted to the vehicle for drivingthe vehicle, the controller stores a plurality of kinds of switchingmaps beforehand, the controller obtains SOC, or a state of charge, ofthe vehicle driving battery, and the controller selects one of theplurality of kinds of switching maps based on the obtained SOC.
 22. Thevehicular power transmission device as in claim 1, wherein the engineside gear mechanism includes an engine side input side clutch forperforming and nonperforming transmission of the power from the engineinput shaft to the output shaft, and the engine side input side clutchis fixed to the engine input shaft.